Josh hooked me up with some cool software called Synergy. It allows you to control multiple computers, through the network, with one keyboard and mouse. Sort of like a virtual KVM, but each computer still requires its own monitor. It’s a wonderful, cheap way to get a multiple monitor system.
I use it at work to control my XP workstation from my laptop.
Oh, you probably already guessed this, but the version in Ubuntu’s repository is old.