I will leave this brief.. install (supported) games on a single pc in the house, and play them on any other network-connected system.. the future will see a linux based version of the software allowing PC games to be played on the PS3.
I haven't tried it out yet, just registered, but, sounds like a good time.
http://www.streammygame.com
Currently supported games:
http://www.streammygame.com/smg/modu...ame=View_Games