How can I alter the tempo of a song? We have a dance competition approach and the song we've chosen is 3:54. The rules say the song cannot be more than 3:30. We have to provide copies of the song on a CD, a USB stick and an iPod/iPad/iPhone which means we cannot rely on realtime slow-down software on an iPhone alone to make the tempo adjustment.

We must record it and save it as a new file and then copy it to all the medium.

I have a friend with a Mac who is willing to alter the file for us -- what does he need to do to change the tempo of the song so it fits in to the 3:30 run length requirement?
Audacity has a change tempo effect you could try in the Effects menu. It might end up making it sound funny, so you will obviously want to listen to it once the effect is applied, but it doesn't simply play it back faster which would change the pitch (that is the change speed effect.)

If my math is right you will want to change it by +11.4% to get from 3:54 to 3:30.