Conspire

Conspire is a collaborative internet whiteboard app for Mac OS X 10.5 or higher. It creates a whiteboard session that you can share across your local network or the internet, allowing you to easily sketch out ideas with remote coworkers, freelance clients or just about anyone, just as you would if you were all standing around a real whiteboard.

Click here for a quick video tour of Conspire!

Conspire sells for $19 and you can buy it from the Pocket Sevens Store. If you would like to try it first, you can download the demo here. The demo disables the Save and Print features, and limits connections to 15 minutes per session (unless connected to a registered host, in which case there is no time limit on connections).