With an iPhone or iPad, there is a virtual music tutor stay with you always in the MusicTT APP. Based on a bundle of folk and classical music MIDI data, the virtual tutor can illustate finger position, keeping time and key changes with great patience. Beginners can follow these instructions to learn how to play lots of musical instruments as an expert step by step. Chords and fingerings of different musical instruments are also listed to help you practice them. Some musical instrument related tools, such as Synthesizer, Metronome, Tempo meter, Tuner and Pitch detector, are provided here too. Open Music Theory (https://github.com/openmusictheory/openmusictheory.github.io) is a public domain, interactive, online text book for college-level music theory courses. To make it easy to access without internet, it is integrated here.