Sharing Bluetooth Keyboard and Mouse
If you have a local network you can use Synergy to share Bluetooth mice and keyboards with up to 5 computers. 


  Synergy lets you easily share your mouse and keyboard between multiple
  computers on your desk, and it's Free and Open Source. Just move your
  mouse off the edge of one computer's screen on to another. You can
  even share all of your clipboards. All you need is a network
  connection. Synergy is cross-platform (works on Windows, Mac OS X and
  Linux).


Here is a good implementation for Mac and Linux: http://code.google.com/p/quicksynergy/