This may become obsolete in oh say about 24 hours but it is a great post – one of many – over at Mac OS X Hints. To quote: Check out MacOSXhints.com or subscribe to their feed. Note: SlimServer was originally designed by SlimDevices (i.e. Logitech) to be used with actual music bridges (hardware) which, obviously, you have to buy from Logitech, so you can play your music collection in your home stereo. However, SlimDevices (i.e., Logitech) was kind enough to open source the program, allowing us to stream music to any software MP3 player capable of playing MP3 from URLs, for free. Here’s how to configure it to stream your iTunes library:
Go to System Preferences and click on the SlimServer icon. Turn the media server on. (You can set it to always run when you log in, or reboot.) Using your browser, open http://localhost:9000 to see the server’s web interface — it takes a little while to open on the first time. Go through the web interface to configure the server according to your needs. I suggest you enable the login/password so nobody can acuse you of illegally distributing music over the internet. From any media player supporting streaming (iTunes, Windows Media Player, Winamp, etc.), go to Open URL in its menus, and open http://1.2.3.4:9000/stream.mp3, where 1.2.3.4 is the IP address of the Mac serving the music files. The media player will login into your media server (and require user/password if you enabled such), and buffer some of the music. This might take one or two minutes depending on your connection. Some players are able to show you the title of the current song, but some aren’t.
To control which music you want to play, use the server’s web interface (http://localhost:9000). Using SlimServer, I can successfully listen to my iTunes collection stored in my Mac at home from my cube at work, 10 miles away.