I know with the std xbox, there's a dongle to connect the headset. I don't know if the 360 will use the same principle, but regardless, is there a headset that will also work with PCs (even if you have to buy a dongle)?
I'm really after a PC headset asap, and having looked around, I've decided to go with the Plantronics DSP-500/GameCom Pro1 (same thing, just different colour), which are USB, and have their own soundcard.
This makes me think they wouldn't work with the xbox, but I'm not sure there's any that do. But the fact that they are USB means I can go to any room in the house, and use the PC online, with joystick, wheel, and now headset, due to USB over Cat5.