http://www.noteworthysoftware.com/composer/download.htm
This program plays for you the NWC Version files that are available for most songs in the woodshed simply by clicking on the button marked "NWC Version" that is opposite the song title. Perhaps the biggest advantage of the software, is that you can control the speed of playback of the song. You can slow it down as much as you want without changing the pitch of the song, which makes it a lot easier to distinguish the notes as you learn your part.
This software is only good for Windows users unfortunately.