looky here
In combination with the Apple MPEG-2 codec, enables all of the bits they deliberately won't let you use in quicktime.....and it's free!
Saves all that tedious mucking about with mplayer (mencoder would be great if a) it could encode stuff to actually play in quicktime player and b) mplayer and VLC didn't have the worst interface bugs ever seen), although if you're doing that "fair use" stuff, you still need the odd slightly dodgy app.
I'm now using it to get the audio out of the Rust Never Sleeps DVD (I can never figure out why they put that crap version of Like A Hurricane on the official concert CD).