Need Help: Capturing Xbox 360 onto iMac

[DoMeShoT OhGoD]

I have looking everywhere for information and I just wanted some advice. I have an iMac and I need to know what kind of capture card/tv tuner I need to record my gameplay on the xbox 360 with high definition and edit them on my computer. thanks (Also I want to be able to play on my HDTV and record at the same time, NOT play off my iMac screen if you know what I mean)

 

[TK B$K]

Same here, ive been kicking ass in COD4 lately and want to put together a montage!