JukeMan
JukeMan is a simple rails app with an iTunes like interface for uploading (or importing from a folder) music into its library, and then organizing that music into playlists. The music and playlists are then distributed (in the background) to all your other JukeMan locations.
JukeMan will run on almost any system that can run MPD (the Music Player Daemon). I’ve written an installer that deploys JukeMan and all its dependencies to a bare metal Debian install: JukeMan Installer