more machines in control

If you ever wanted to have two or more machines use single mouse and keyboard, no matter what OS they're running, here it is - Synergy2. Connect the machines with some network (I'm using direct eth over firewire), configure it, and it works like charm, shares clipboards etc.

If you need just two windows machines to be cooperating, and want quite config-free nobrainer soluiton, check SDE3K. It's faster than synergy, which jumps the mouse time to time, but it tends to crash a bit, can't do mouse wheel on secondary screen, and you can't configure it much.