First things first: the Uilleann Obsession pages should be every piper's first port of call on the internet.

Not unrelated to that is the Southern California Piper's Club which has a nicely organised list of tunes that they are working on. They provide an audio file for most of these, so there's no confusion with names - you can learn it right off the audio track. If you're wondering what to learn next, this is a great place to start.