Multi-MPD (Music Player Daemon) is a web-based client for controlling multiple instances of MPD with multiple outputs each, managing output routing, playlists, and browsing and loading net radio streams (eg Shoutcast, Sky.FM/Digitally Imported).
DBsong is a php/mysql web application which provides democratic music selection. Users vote on the songs they want to hear, which appear in the playlist accordingly.
It is designed to be used with Icecast2 and Ezstream to stream MP3s over a network.