Multiple OS X Desktops using OSXvnc: "Simply put, Mulitple Desktop Sessions allow more than one person to use your Macintosh computer at the same time!

In Panther (Mac OS 10.3), Apple introduced ‘Fast User Switching’ which allowed additional users to log on to the mac without the original user logging out. Instead, the original user's desktop was carefully tucked away and could be switched back to when needed.

Now in Tiger (Mac OS 10.4) all those desktops can be accessed simultaneously using OSXvnc. This allows multiple users to be logged in, each using his or her own desktop on the same Mac"