I suppose any decent sound editor would be capable of doing that - wouldn't be much more than changing the pitch of the track, or if they only changed the voices but not the music, then also some vocal cut filter in addition to that would probably be sufficient If you want to get really accurate or clean-sounding results, a clever mix of those and non-vocal versions of the track you're editing will also work

I'd probably use CoolEdit myself if I wanted to do that, Adobe Audition or the free Audacity could probably both do it as well, amongst others, though I haven't checked them myself