[Captain Obvious]

Is it possible to remove the sound from an AVI and make it into a stand alone audio file?

[Nap]

You will need QT Pro to do it. Open the avi file, go to the Edit menu and select "Extract Tracks." You will then be able to choose the video or audio track to extract. After you have the audio in a separate window you can choose "Save As.." and choose the self-contained option to make a completely independent file of the avi audio track.

[Uncle Skeleton]

or iTunes if you're cool with re-encoding. I extracted a butt load of ogg files from ogm files once and batch converted to aac with iTunes (ogg qt component installed). very easy.

if you don't want to re-encode and also don't want an mp3-in-mov (or whatever format it's in) it's sometimes possible to open a one-track mov in HexEdit and delete the mov header and be left with a valid mpeg/mp3/whatever file.

[Jacke]

If it's MP3 audio in the file you can try DivX Tool, which has the ability to save audio.

If you want to do as Uncle Skeleton said, open the audio-only QT file in HexEdit and search for "mdat". There will be two entries close to each other, delete the data up to and including the second entry.