MP3 Keyshifter is a breakthrough piece of software that allows you to change the key of any audio track and save the modified song as an MP3 or WAV file.  If you use backing tracks you can now change the key to suit your vocal range at the press of a button!
The only way to be 100% sure that the key of a backing track is comfortably within your vocal range is to sing along with it in real-time.  Unfortunately this can only be done when the track has been purchased and often leads to tracks being left unused.  Now you can buy your backing tracks with confidence - knowing that you can fine tune them to suit your voice.