Source: http://lifehacker.com/5515093/qsynergy-makes-multi+system-control-easier-and-prettier
Windows/Mac/Linux: It continues to amaze, just how easy it is to control multiple computers with a single keyboard and mouse with Synergy. QSynergy clamps a crisp, generally easy-to-grasp interface onto Synergy, giving it the update its long deserved.
QSynergy isn't the first update to Synergy we've come across—Synergy-Plus added some updates and bug fixes to the original. QSynergy adds a few bonus features of its own, but its main benefits involve how easy it is to install on Windows, Mac, or Linux systems, and the setup tools and design put into it. Arranging the left-to-right arrangement of multiple systems is done with a grid interface, the crude, Windows-98-era options panels are cleaned up, and with just a little tweaking, you're managing multiple computers as if they were just multiple monitors on one grand Mother Brain.
QSynergy is a free download for Windows, Mac, and Linux systems. Thanks for the tip MePerson!