La Touche Musicale allows you to learn the songs you love on piano. Connect your MIDI keyboard to your device and learn very quickly.
Flowkey - The easiest way to learn piano with your iPhone or iPad
Synthesia - A fun way to learn how to play the piano.
Melodics - Melodics is a desktop app that teaches you to play MIDI keyboards, pad controllers, and drums.
Piano From Above - Piano From Above is a program that turns learning the piano into a videogame.
Playground Sessions - Online piano learning game.
Simply Piano - Fast and fun way to learn piano