La Touche Musicale allows you to learn the songs you love on piano. Connect your MIDI keyboard to your device and learn very quickly.
Virtual MIDI Piano Keyboard - Virtual MIDI Piano Keyboard is a MIDI events generator and receiver.
Flowkey - The easiest way to learn piano with your iPhone or iPad
Melodics - Melodics is a desktop app that teaches you to play MIDI keyboards, pad controllers, and drums.
Linthesia - Linthesia is a game. A game of playing music! You only need a MIDI file
Synthesia - A fun way to learn how to play the piano.
Free Piano - FreePiano is a virtual MIDI keyboard and a VST host for windows.