ChartGo is a site I learned about from Larry Ferlazzo and is one of many for creating online graphs. There are many sites that do the same thing, but if you want something simple w/out all the "bells & whistles" then ChartGo is the place for you.
To get started is simple just click on chart info and enter the data of your graph. After that you can click create graph or go back to the main screen to determine the type of graph you want (by default it is pie). Once the graph is created you have the option to print, save, or link.
What I wish CG did better was allow users to import data such as Excel (or xls). Also, to really make an impact I would've added some subtle flash effects" that other sites such as Widgenie or Rich Chart Live.
Give ChartGo a try by clicking here.