ABC Teach is a great site for educational resources. A teacher can create worksheets, find lesson plans, and even search through school appropriate clipart. There are even resources for interactive whiteboards.
ProProfs is a great "all in 1" site for educators/students. What I mean by that is that there is so much to do here that this is almost like a one stop shopping of sorts. This site has: educational games, flashcard creator, quiz maker, and even a poll creator.
Youngzine is a site I just found out about from Free Technology 4 Teachers. This is an excellent site for kids/students to find out current information on the web. Here is a quote straight from their site, "Our goal is to help parents and educators create a vibrant community of globally aware young citizens in an increasingly connected world. Along with news stories written specifically with our young audience in mind, Youngzine strives to inform using fun trivia, compelling visuals and videos."
Reel is a wonderful site for creating amazing presentations by uploading files, PPT, or PDF's. Once the presentation is completed a user can embed it into their site or share a unique URL w/ others. Also, there is thumbs up/down button for others to click to rate your slideshow.
Pixenate is a nice free online photo editor. As w/ most photo editors user can: crop a photo, rotate, and resize an image. Also, there are some nice options such as drawing and teeth whitening.
Chess Kid is a fun/safe place for kids to learn how to play the game of chess. This is ideal for those that are teaching chess club or have students in chess club who want to practice their skills and learn the rules of the game. Best of all, parents control all of their child's online access.
Library Thing is a nice site for cataloging books and then sharing your thoughts and feeling w/ others. Think of it a social network for books a la Shelfari. A user can rate books on a star system (ie, Amazon), connect w/ other users, etc etc.
Social Decks is a nice site for creating flash cards on any subject. Flash Cards are shared w/ others via a unique URL and images can be added to cards too. A user can search through online cards as well.
E-Learning for Kids is a great place for students to find courses on any number of subjects. This site is geared towards kids ages 5-12 and the courses are broken down by subject and grade. These online courses are easy and fun for the kids to do and cover everything from math to computer skills.
Synonym Finder is a great online thesaurus. Not only can users find synonyms to their words but antonyms and definitions as well.
Words Steps is a great site for trying to learn a foreign language. On this site a user can create a word list that they want to learn. This list can contain images to help the person learn, as well as audio to help pronunciation. WS also has a mobile app to help people learn on the go.
Critical Past is a great free site for history buffs or teachers. This site has over 57,000 videos and 7 millions stock-free images from the last 100+ years. What makes this site so great is the ability to search for data by decade, subject, or even find out what happened on your birthday.
SchoolRack is a nice site for teachers to create a free website or blog. There are some nice features as creating a student or parent portal for sharing information. Also, a teacher can create a mailing list which is nice when wanting to send an email to a group of people. A teacher even has the ability post and monitor classroom assignments.
CalcMoolater is a great site for finding calculators for all types of occasions (ie, student loans, mortgage, etc etc) The way this works is selecting the category for the type of calculator you need and the entering the data it asks for.
Classtell is a wonderful site for educators to create an educational website. This is easy to do w/ a nice user interface. Also, a teacher can password protect any on their webpages or control who can view them for excellent privacy controls.
Knotebooks is a great collaborative site for teachers and students for taking notes and then sharing w/ others. Not only can student take notes but they can create study guides and share them online. Also, teachers can create educational resources and share them as well.
Scour is a new (beta) search engine that index's through the most popular search engines (ie, Google, Bing, Yahoo, etc.). What makes Scour unique is that the results that are returned can be commented and voted on to help users select what's best for them.
Study Ladder is a site I just found out about from a Facebook ad. This is a great site for educational resources (ie, worksheets, lesson plans) as well as educational games. SL is one of the fastest growing educational sites around and has lots to offer.
Vocalyze is a site I just found out about from Free Technology 4 Teachers. This is a great site for having web content read to you. This is ideal for those that like to multi-task and don't have time to read news on the web, or for those who may be visually impaired and can't read the way themselves.
School Circuit is a nice looking free online environment/grading tool for educators. This is a place where students, teachers, and parents can come together through collaboration (ie, grade tracking, messaging, etc etc). While this is a free site, a user gets more features through a paid license such as reporting and data storage.
Panfu is a fun/safe place for kids to explore a virtual world. Here is a description from their site, "Panfu combines play, knowledge, discovery, fun and safety. We provide a place for creativity, playful learning, social interaction and adventure for your child." 
Celly is a wonderful free site for using mobile phones/text messaging in the classroom (found out about from a member of my PLN on Twitter). There is a lot to like about using Celly such as: creating a chat, alerting, and even using a curator to approve messages before they get posted (ideal for education). Also, it's ideal for taking notes, interacting w/ web (no phone is actually needed), etc etc.
Polltogo is a wonderful app for any mobile device for creating polls and getting instant feedback. Ideally, this is a much cheaper solution then for those districts that use Activotes or some type of voting system w/ their smartboard.
Pic Treat is a nice site for editing a profile photo. This is done by uploading any photo (profile or face pictures work best) and then waiting while it smoothes skin, removes red eye, etc etc. When finished it shows you a before and after picture and then can be shared among favorite social networking sites (ie, Facebook, Twitter).
Brain Nook is an excellent site to help kids strengthen their math and english skills. This is done by roaming through safe virtual worlds while playing educational games. Also, there is the ability for teachers to add a class so their kids can play together.
Learnopia is a learning management system for teachers and students. This is a great place for students to search for online classes that are ideal for them. Also, this a nice place for educators to find free resources or even teach classes online for free or a price.
Skloog is a new (beta) site for bookmarking sites in a visual way. This is done by creating thumbnails of a users site and then being able to tag them and arrange them in anyway. Also, a user browse lists created on Skloog.
Braineos is a new (beta) fun site for students for playing educational games to help them study. These games cover all types of subjects such as: Chemistry, Spanish, Math, etc. Also, this is a nice site for finding and creating flashcard which can assist in learning a subject.
Simple K12 is a site that I've known about for quite some time but happily reminded about from David Andrade's wonderful blog. This is a site dedicated to helping students/educators bridge the gap between technology and education and integrate them w/ 21st century technologies. 
We Video is a site I just found out about from Free Technology 4 Teachers. This is a great site for creating collaborative videos. This is done by either choosing stock video or uploading your own and the editing the footage (trim/crop etc.). Being "web 2.0" in nature a user has the ability to invite others to collaborate/edit a video as well.
BO.LT is a wonderful site for tagging/recommend websites. This is done w/ a very easy to use innovative interface that allows user to create "bo.lt" page by copy and pasting a URL. That is all a user has to do. They are then given a unique URL that can be shared w/ others. This new page will have a bo.lt icon which allows people to leave comments or share via Facebook or Twitter. Also, there are a bunch of nice shortcuts that users can do for tracking or shortening URL's.
Tabblo is a nice site designed by HP for creating a story w/ photos and text. This is a very easy site to use and when the product is finished a user can share it w/ others online, email, or even view it in a slideshow. This could be a good site for digital storytelling/slide shows.
Threddie is a nice site for brainstorming online. This is done w/ a nice user interface and is free for a personal account. A business account does cost money but allows for more storage. A nice feature is the ability to customize your own URL.
Draw a Stickman is a fun site I learned about from Larry Ferlazzo's award nominated blog. It's simple to do and fun to watch the stickman walk around and talk out loud. Once an animation is done a user can share it w/ others via Twitter, Facebook, or email.
TXTNLRN is a very innovative site that is designed to teach and learn through text messages. Right now there are bunch of classes for writing, computers, etc. All enrollment is done via a text and TXTNLRN is also available spanish.
Over the last few years online tutoring sites have really boosted in popularity. The reason for this is people just don't have the time or the money to spend at an actually tutoring center. Online Tutoring is an ideal solution as it can be done at home on a computer or mobile device and is usually a much cheaper alternative. Also, online tutoring/teaching is a nice way for educators to earn some extra money doing what they love to from the comfort of their own home and setting their own schedule. Plus, students should love the ability to view and choose courses that work for them.
YouTube Teachers is a site I found out about from a promotional email. This is a site that is geared to help teachers use educational videos in the classroom. Also, it shows teachers how to record themselves and implement video that way.
SimpleMeet.Me is a site I found out about from Free Technology 4 Teachers. This is a simple (ha) site for creating a private chat. This is done by sharing a unique code w/ others that lets them enter a private room for chatting.
Notefish is an excellent site for taking notes of web content. A user can grab any content from a web page and add it to their own notefish page. Also, a user can: drag-n-drop, color, tag/annotate, etc etc. Once a page is done it can be shared w/ others online.
Study Stack is an excellent site for creating flash cards. Also, a user can search through pre-made flashcards to find what's best for them. Another great feature are the educational games a user can play to help them study. There is a nice mobile app which works nice too for the users who prefer using mobile devices.
Highlighter is an excellent site that allows readers to annotating, highlight, comment, and share any text on your site. Another nice feature is the analytics that allows user to track exactly what people are reading on their site (ie, commens, shares, etc).
