I have a few musicvideos but i couldn't find the MP3. So what I did was, I played the vid with WindowsMediaPlayer and record it with SoundForge. After that, you can save it to wav, midi,mp3, divxsound, and lots more. If the recorded music is not satisfactory, you can tweak it up with SoundForge i.e you can add more bass, or turn up the volume. You can also Normalise it.