Synergy let's you share your keyboard and mouse with multiple computers, and can be setup to operate multiple computers with just one keyboard and mouse.
The official version lacks keyboard broadcasting support, which is used when "multiboxing" with games like World of Warcraft. There is a patched version of Synergy 1.3.1 available that features Keybaord Broadcasting support, but has Windows binaries only.
This is a modified version of Synergy 1.3.1 that features Keyboard Broadcasting support, allowing it to be used as a "Multi Boxing" solution when playing games like World of Warcraft. The download archive has windows binaries only.