A nice site for creating online charts and graphs; it has a built-in chat feature for collboration.

Cacoo - Real-time Collaborative Diagramming & Design from Nulab Inc. on Vimeo.

chartle.JPG tears down the complexity of online visualizations - offers simplicity, ubiquity and interactivity instead.
Chartle Tutorial
Create a Graph
Here you will find five different graphs and charts for you to consider.
Graphing Tutorial
Dabbleboard is an online collaboration application that’s centered around the whiteboard. With a new type of drawing
interface that's actually easy and fun to use, Dabbleboard gets out of your way and just lets you draw. Finally the whiteboard
enters the digital age!
Dipity allows users to create free timelines online. Digital timelines are a great way to increase traffic and user engagement on your
website. Dipity is the fastest and easiest way to bring history to life with stunning multimedia timelines.
Simple Diagrams
Simple Diagrams is a free download desktop application useful to create diagrams and flowcharts. This easy-to-use tool turns ideas and concepts into a visual explanation. You merely drag and drop icons from the available library onto either a chalkboard or a whiteboard background. Insert personal photos or type written notes on virtual index cards or post-its directly into a diagram.