Metropol

I have a mov video and an mp3 audio, and wish to create a file with the mp3 audio on top of the mov video.

How would I go about this as simply and cheaply as possible?

The easiest way to do so is to use QuickTime Pro. As long as the music (mp3) is not protected, you can simply add an audio track to the movie.

Similiar subject, is there a way to replace the audio on an MPEG2 file without re-encoding the whole lot?