The marvelous SLIMP3 device is a hardware and software solution to stream music from your computer out through your stereo. However, just using the SLIMP3 music serving software, which is open source and free, you can send multiple MP3 music streams to any computer that can play MP3's from a stream. It has advantages over iTunes music sharing: (1) cross platform, (2) multiple user-controlled music streams.
First, get the SLIMP3 server software. Install the software and then use the SLIMP3 preferences pane to start the server. It should auto-detect the music files in your iTunes library. If your computer is at IP address 192.168.0.101, then the SLIMP3 music server can be controlled from your web browser by pointing the browser at 192.168.0.101:9000.
Go to iTunes and under the "Advanced" menu, and then select "Open Stream" and enter:
http://192.168.0.101:9000/stream.mp3Go back to your web browser and select a song from the playlist on the left hand side of the web page. On the upper right hand corner there should be a popup list of SLIMP3 clients, and the IP address of your machine should be listed, since you have iTunes running as a client. Click the play button and the music will play through iTunes.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20030521160642537