The latest unibody MBP or the previous MBP?
Mine (the previous) output socket is DVI.
There are two dongles available, the first can output analog video (RCA or S-VIDEO) the other dongle at a better VGA.
The Unibodys output socket is MICRO-DVI.
There are three dongles avilable, between them they can output MICRO-DVI, DVI or VGA.
Basically, an older MBP can easily play on an older TV, whereas the newer models will only play on the latest TV's. If you want to play vice versa you will probably need to look into a scan converter.
So, buy a TV / laptop accordingly
See the dongles for yourself here:
Video Devices - Apple Store (Australia)