One Keyboard, One Mouse, Many Computers
My work environment consists of a desktop computer and a laptop. I do all of my development work on the desktop and use my laptop for instant messaging, email, testing, and other miscellaneous tasks. The only problem with this arrangement is that it requires two keyboards and two mice - not an optimal workspace arrangement. I found a very useful open-source utility called Synergy that solved this problem nicely. Synergy allows you to use a single mouse and a single keyboard to control as many computers as you would like - similar to remote desktop, only different. Interestingly, Synergy also allows you to "cut and paste" from one computer to another - sort of like a shared clipboard. Seeing Synergy work for the first time can be a bit startling but after the initial shock, you begin to see the possibilities.
Synergy can be a bit tricky to set up. In a Synergy installation, one computer is configured the server and one or more computers are configured as clients. On each participating workstation, you must tell Synergy the physical orientation of each participant. For example, my laptop is "to the left of" my desktop and my desktop is "to the right of" my laptop. It seems strange that I have to do this on both computers, but it is necessary. If you run into any problems, read through the FAQ where most common configuration issues are addressed.
Give it a try. I think you'll find Synergy to be very useful.