I alternatively use three computers and I've been using Mouse Without Borders to control all three without having to constantly plug/unplug the mouse and keyboard between them. Very useful utility.
My main unit is a netbook, which is fine for most tasks, I even use it for programming, but there are times where I either need to move a ton of files for archiving, or need a really powerful CPU for video processing, and that's when the other two gets turned on (I have three monitors, and all the video inputs are filled up so I can do various combinations). Unfortunately, I recently got a mac mini and now I'm looking for an alternative that will let me control the mac as well. Any suggestions?
The one I've found so far is thishttp://www.keyboard-and-mouse-sharing.com/download.php
It's $25 per PC tho so it's very expensive. I've considered VNC but it uses a ton of network bandwidth and CPU.