Flat - Online collaborative music score and tab editor, accessible from any device
Violin by Trala - Violin by Trala is a music learning app that is designed specifically for Violin users.
Flat for Education - The best way to teach music to your students
Simply Piano - Fast and fun way to learn piano
Transposr - A free and simple way to transpose your sheet music or MP3.
MuseScore.org - Create, play back and print beautiful sheet music with free and easy to use music notation software MuseScore. For Windows, Mac and Linux.