My new PM pointed me to this tool. It's basically like terminal services. But there is an extension to the tool called Win2VNC which allows you to use one keyboard and mouse on 2 screens. Let me explain. I recently bought a notebook, so now I've got my desktop work pc and my laptop sitting next to each other on my desk. With VNC installed on both machines, I run Win2VNC on my desktop pc ( that has the keyboard and mouse connected) and tell it that my laptop screen is to the left(west) of my pc's screen. Now when I move my mouse to the edge of my pc's screen it disappears and reapears on my notebook screen. Then the mouse and keyboard relate to the machine where the mouse pointer is on. Very cool. You can even copy/paste between the 2 machines.

Of course, it's open source.

http://www.realvnc.com/
http://sourceforge.net/projects/win2vnc/