Wohooo.net - Create Your Own Online Radio Station
EarMaster - Professional software for ear training and practical music theory on Windows and Mac.
Listen2MyRadio - Stop dreaming, start streaming. Free and premium Shoutcast and Icecast audio broadcasting.
Meludia - Listening exercises and to sharpen your ear and music theory skills
SOUNDS - Discover music with friends
GNU Solfege - GNU Solfege is free music education software.