Synergy, wow, this is one of the most useful tools I've found in a while. It's a software KVM basically. A single PC's keyboard and mouse can be shared between many machines. In addition it runs on many operating systems including Linux and Windows. At the moment I have it set up to use my desktop Linux box's keyboard and mouse on my Windows Media Center laptop. The Synergy web site is here.

http://synergy2.sourceforge.net/

To use it on Linux as a server you need to configure a .synergy.conf file in your home directory. I've given mine here, it's pretty small and does the min, but it works great.

section: screens

 linux-box:

 windows-laptop:

end

section: links

 linux-box:

   left = windows-laptop

 halfpint:

   right = linux-box

end