SmartMusic: access to performing and recording music at home
Musescore: a free program that allows you to compose your own music!
MusicRacer: A set of music games you can play-Note Names, Fingerings and Music Terms 101
MusicTheory.net: Exercises for note naming, intervals, chord diagrams, ear-training and lessons on music theory
Making Music Fun: Printable resources for music learning, such as staff paper and music history
The Music Interactive: Games and apps for music