Multiple Desktop Sharing with Synergy

Synergy is a fantastic tool It allows you to use a single Keyboard and mouse hosted to a machine to be interactively shared across multiple Machines and accessing their display.

So if you have 2 or more computers Side by side, and you don't mind the Screens being there, but you really hate having a swarm of Keyboards and Mice all over this is a graceful solution.

Start here, for windows only this is all you will need.
http://synergy-foss.org/

"Synergy is Free and Open Source Software that lets you easily share your mouse and keyboard between multiple computers, where each computer has it's own display. No special hardware is required, all you need is a local area network. Synergy is supported on Windows, Mac OS X and Linux."

If you have a Mac or Linux Desktop you would like to add to the mix, I strongly recommend QuickSynergy.
 http://code.google.com/p/quicksynergy/

How i did this with My Ubuntu and Windows XP Machines.

I installed the QuickSynergy application from the Ubuntu Repository (it installs at version 1.3.1), Then i downloaded the Most up to date Synergy package from the synergy project which is version 1.4.2 and installed it form the command line which updates the synergy binaries, but leaves the QuickSynergy interface in place! "sudo dpkg -i synergy-1.4.2-Linux-x86_64.deb".

From here its just a matter of configuration which is pretty simple. Pick on for the server, and then add clients to that machine, the server is the  computer that has the keyboard and mouse you want to use.

A quick rundown of setup from Linux Magazine

 Launch QuickSynergy on the machine that is going to be the server (or Share in QuickSynergy terminology) and type the hostname of the netbook you want to control in one of the four fields. Each field allows you to specify which border of the server's screen should act as a switch. For example, if you enter the hostname in the Right field, you can switch to your netbook by moving the mouse cursor to the right edge of the server's screen. The cursor then magically jumps to the netbook's screen, and you can use the mouse and the keyboard with your netbook. Note that you must enter the hostname not the netbook's IP address. To find out the exact hostname of your netbook, simply run the hostname name command on it. When you've entered the hostname, press the Execute button to start the server. Launch then QuickSynergy on your netbook, switch to the Use tab, and enter the IP address of the server in the Server hostname/IP address field. Press the Execute button and you can then use QuickSynergy to control your netbook.