Total Media Extreme (PC software provided) only runs.....well as stated, on a PC
As for the Mac, I am very pleased you have asked this question. I have been searching the internet for this answer you have asked for, but cannot find it anywhere.
HDPVRCAPTURE is a Mac software, however you can only record for 2 mins and it saves the file as a M2TS file, which cannot be opened on a mac. So is rather stupid really. You would have to carry it over to a PC to watch what you have recorded.....so I uninstalled it.
EyeTV 3.0 is a probs your best option as Yatezy said. However this will cost you $70 to buy/download.
If you cannot afford this (like me) then I tried it as a torrent which worked fine as long as you dont EVER close the application. If you do, you will have to go through the sign up process again. And when it asks for a Serial it will have blocked the serial you used the first time round. And I could not then find another working Serial
So I have had to put a PC laptop between my iMac and xbox to use to record with my PVR. Until I find an answer to the question....or get money
Hope this helps a little, or gives you a little know-how. And again, if I find anything out I will sure post it here