I'm not sure when this has been introduced, but probably with 10.2.5. The Displays control panel now has extended options when the computer is connected to a TV. It's now possible to enable overscan, a feature that was available on Mac OS 9, but has been missing on X for a long time. Now, for example, DVD viewing is possible as expected - without a black border around the movie.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20030430164411124