Metronaut - An app to help you play classical music
Virtual MIDI Piano Keyboard - Virtual MIDI Piano Keyboard is a MIDI events generator and receiver.
Violin by Trala - Violin by Trala is a music learning app that is designed specifically for Violin users.
EveryonePiano - Everyone Piano is the best free computer keyboard piano software, which supports downloading 3 types of music score formats like stave, right and left hand numbered musical notation and EOP file.
Simply Piano - Fast and fun way to learn piano
Synthesia - A fun way to learn how to play the piano.