Synergy is a pretty cool piece of software, that I’m sure I blogged about ages ago at the Other Place™.
Synergy lets you easily share a single mouse and keyboard between multiple computers with different operating systems, each with its own display, without special hardware. It’s intended for users with multiple computers on their desk since each system uses its own monitor(s).
I’ve used it to connect my laptop to my PC … three screens is cool! We have folks at work using it to connect two PCs running Windows 2000 to Mac OS X.