This is a program I wrote and forgot about awhile back. It basically generates a .html file saying what I'm currently listening to, and uploads it to my server. See http://www.javaop.com/~iago/xmms.html for more info, but I don't run it anymore.
If anybody wants the source, here you go:
http://www.javaop.com/~iago/xmms-nowplaying.tgz
The most important part of that is probably the Makefile -- it links in the proper libraries to access xmms.