You don't actualy record the incoming signal to your XBOX360. It simply streams Media Center as an Extender. To do this you need:
1 Windows MCE2005 SP2 rollup2
2 Router, Hub, or at least a Crossover Cable
3 Balls of steel.......................(You never know)
Actualy the process is quite simple
IF YOU HAVE WINDOWS MCE If you don't have it
GET ITYou would simply plug your crossover cable into a correctly configured Media Center Edition PC then follow the onscreen instructions in the "Media Center Extender" setup on your XBOX360. If you have your windows MCE PC updated per the instructions given to you when attempting to configure the Media Center Extender function of your XBOX360 you are good to go. The whole process should run smoothly. I had it configured by 1:00 am on release date. I was #13 in line and had it purchased by 12:20 am. It was one of the first things I did with my new XBOX360