Simply Piano - Fast and fun way to learn piano
Sibelius - Sibelius is a virtual score creation tool which allows composers to easily create new piano scores, developed by Avid.
Melodics - Melodics is a desktop app that teaches you to play MIDI keyboards, pad controllers, and drums.
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.
Yousician - Learn to play music at home, at your own pace
MuseScore - Our goal is to let musicians from all over the world create and share their works, as well as to make learning music exciting, easy and available for all.