Synergy+ (synergy-plus) lets you easily share a single mouse and keyboard
between multiple computers with different operating systems, without special
hardware. All you need is a LAN connection. It's intended for users with
multiple computers, where each system uses its own display. It's a little
like having a 2nd or a 3rd desktop.
Synergy+ is a maintenance fork for implementing bug fixes to the original
Synergy, which hasn't received any source updates or new releases since 2006.