I put together a little app to tell me when bands I like come near me. I figured I might as well let other people use it, too. I even found a few bands that I would have missed while building it, so that's a plus.
Basically, you upload your iTunes Library.xml file. Then I parse it and email you the bands that play near you.
http://www.bandidate.com
Anyway, that's all it does. I'm curious what you people out there think. If nothing else, it was great for getting better with Rails. And it was pretty fun.
Except that you limit it to people who use iTunes? You're shutting out a whole lot of people.