Now available as a free trail, this audio processing app lets you change the speed and pitch of non-DRM songs in your iTunes library. Pretty handy for learning songs. Obviously there are a few limitations on this one (see below). So if you find a use for it, the full version is only a couple of dollars. For something with a few more features, Anytune is a great alternative.
All in an incredibly responsive and easy-to-use app. Ideal for transcription, learning songs by ear, or just listening to your music library in a new way.
• Simple uncluttered user interface
• LiveScrub™ : listen as you drag/hold the waveform
• Super-easy single-button looping feature
• Load any song in your music library*
• No ads or in-app purchases
LIMITATIONS OF LITE VERSION
• Max song duration 5 minutes
• Speed range 60% to 100%
• Pitch shift +/- 2 semitone
FULL VERSION ADVANTAGES
• Max song duration 60 minutes
• Speed range 0% to 250%
• Pitch shift +/- 12 semitones
• Keyboard/spectrum display
• Open Dropbox files
• Open email attachments
*Except Fairplay DRM-protected files (i.e. very old, pre-2010 iTunes purchases). Songs in formats other than aac/m4a (e.g. mp3) may load a bit slowly in iOS 5.1; iOS 6 recommended.