From Song Galaxy:
Do you want to sing along with a backing track, but the key is too high? Or would you like your song to play a little faster? You've found the right software: ... MP3 Key Changer V2 allows you to transpose the key and change the tempo of any MP3 or Wave song file. Transpose song key by up to +/- 12 semi-tones. Adjust tempo by up to half or double the original tempo. Demo version allows you to play only the first third of a song, and allows 3 saves before you need to purchase and register.
Version 2 offers Improved saving algorithms for Higher Quality editing! Plus, you can now listen to a High Quality preview clip to check your adjustments before saving. And, of course, MP3 Key Changer is still as easy to use as ever. Users of Version 1 are invited to upgrade to Version 2 and benefit from the improved quality and features, upgrade code can be purchased at our webshop.