Gonic - music streaming server / free-software subsonic server API implementation - sentriz/gonic
Openwhyd - Collect and Share the tracks you love.
Swing Music - Beautiful and fast music streaming server.
Zoff - Collaborate on a live music and video playlist with your friends.
MusicDB - MusicDB is a music manager, server and player that focus on music.
SoundCloud - Enjoy music & follow favourite artists