Hey,
I have just completed a web app which some of you may be interested in...
D u s t y T u n e s | Let your music collection see the light....
It basically allows you to upload your itunes library file (only the xml file....not the actual mp3's). The site then parses it and gives you your own webpage with your entire music library organised into a nice list which you can share with friends, on blogs, messageboards etc.
You are also able to search for tracks and listen to previews of them. There are millions of previews available (everything available for sale in the itunes store.)
Give it a try and let me know what you think...