Record Tutorials And Demonstrations
A lot of people use the remote control software VNC to talk between all manner of computers and operating systems. Using VNC you can control a Windows machine from a Mac, or Linux from Windows, etc.
Here is a really cool tool to help you record sessions to Flash format. It makes it easy to record a tutorial or demonstration of something on a computer and distrubute it so anyone with Flash in their browser can watch: Vnc2swf - a VNC recording tool for Flash