MyTunesRSS is a nice little app that lets you publish your iTunes library on a web server.
You can access this server with any web browser, search your iTunes music library and create an individual play list. The play list is published as an RSS feed with the feed items containing links to the music files. These files are served through the server as well.
You can subscribe to these RSS feeds as podcasts. Nice. I’ve only played with it a little, so I’m not quite sure how these RSS feeds are updated (if they are updated at all). The only minor annoyance is that while the iTunes library is searchable, it’s not browsable (so you have to know precisely what you’re looking for). You can see mine here.