I have built my own, albeit modest, celestial jukebox.
I have copied all the music files from my iBook to my server and am running a version of Apple’s Multicast DNS daemon (aka rendezvous or zero-conf) with a freeware implementation of the iTunes server. Now I can serve up my music files without the iBook, from anywhere on my local network.
I used rsync to copy everything over and will be setting up a cron job to handle that automagically.
The last hurdle is to run all the files through hymn to make sure I can always listen to them.
I’ll write up a HOWTO presently. Coincidentally, MacWorld magazine has an article on how to build a music server, but there’s not much challenge to setting up an additional Mac and using iTunes’s Sharing. Who has an extra Mac laying around anyway?