SlideSix is a website very similar to SlideShare for hosting slide shows. Not only can a person upload any: PP, Open Office, or Keynote presentation but they can record audio right from the site. This is ideal when wanting to create a sound track/narration to a slide show and not having to worry about uploading a audio file.
I'll probably be adding some presentations up there shortly!!
I highly recommend checking out SlideSix by clicking here!!
For a much more detailed review, check out Free Technology 4 Teachers!