Meludia - Listening exercises and to sharpen your ear and music theory skills
Recursive Arts Virtual Piano - A realistic 3D piano keyboard with flexible and automated song accompaniment of popular songs
GNU Solfege - GNU Solfege is free music education software.
VirtualPiano.eu - VirtualPiano.eu is a web-based tool that provides you the virtual Piano to play songs, learn the piano tunes, and create soothing song compositions.
Perfect Ear - A simple yet advanced application for improving your solfege skills.
PianoPlays - PianoPlays is the virtual piano tool that allows you to play and practice the tunes of your favorite songs.