Slowing down the playback of an audio file without changing its pitch?

Question

I am working on an application for college music majors. A feature i am considering is slowing down music playback without changing its pitch. I have seen this done in comme

Answer 1

audacity does it out of the box and it's free. THere are several plug ins for mp3 players as well that are free. Apparently it's pretty easy to do with an mp3 since it's already coded in the frequency domain.