MATTGEE  This program is fantastic. I use it to control a mac media center from my laptop. The latest version adds support for zooming, which was the only flaw I'd encountered.

There is a similar utility called Synergy (not the sync utility of the same name) which is cross platform. But if you're using macs, this is definitely superior. The bonjour support makes it super easy to get started. And the details like drag-and-drop, clipboard syncing, and arranging remote displays are very well executed.  
(Version 1.0.1)