SwingDJs

There are a lot of soundies available now on DVDs like this one, as well as online.

A lot of the music is excellent, but as far as I know, the music was not recorded separately. So, does anyone know if it is possible to extract the audio only from a soundie, for example in MP3 format?

Very easy method is to play the DVD on your computer/laptop and use Audacity to record the audio. You can export that as an mp3.

I've used other tools to extract the audio... any "Demuxer" will separate the audio and video channels. Unfortunately the audio source from many AVI files and such is substandard.