I use Elgatos EYE TV hybrid, it has a RCA input and you can plug your PS3 into it and play on your mac as well as watch TV. You can also record anything you plug into the eye tv. The only problem is that there is about a 1/2 to 1 second lag when recording something like a games console, so what I usually do is play the game and then record the games replay function (if it has one) Some people use a scart splitter which splits the scart into 2, so one end can record on your mac book via the eye tv and the other end can be plugged into a TV, then just play the game as normal on the TV with no lag and it works fine.
This is quite a pricey option, with the eye tv hybrid coming at round about £100