For Fans of Flatpicking Guitar Magazine
I use Song Surgeon. Very cool, very feature rich. Able to change pitch and speed w no loss of fidelity; can easily create lead or rhythm tracks to play against; can create a stand alone executable of a song to send to your band mates and on an on. If you want to learn how to play by ear, this is a terrific tool. www.songsurgeon.com
I think the free (unregistered) version of ASD will (forever) work on the first 25% of a sound file, up to 3 minutes. So, if you really don't want to pay the software developers their due, you can simple paste 4 copies of a song together with any of many free sound file editors - for instance, 'Audacity' is a very powerful freeware (PC only) multitrack recording studio and sound processor.
Try 'em both in the free version - there is enough there to determine which you like most (probably SS), then buy the full version; IMHO, they are both worth the money - extremely useful, a constantly used tool for me.
I use Audacity. It's free and super easy to use for most recording, formatting, mastering, etc. Works on most audio formats.