This post is quite old. CherryMusic has improved a lot since then. For the latest version and information on CherryMusic, please visit http://fomori.org/cherrymusic
I recently wrote a Music Streaming Server in python, that allows you to listen to your music inside a browser, no matter where you are. It is called CherryMusic and features a standalone webserver based on cherryPy as well as JPlayer, a HTML5/Flash music player. It indexes your data for fast search using a sqlite database, so there is nothing to setup for you, just download the sources and off it goes!
In my tests it works perfectly with many thousand indexed files: searches are returned immediately, even on my little home server.
After the break you can find some screenshots of it in action.