Hi Tim,
Well, as Layne mentioned, I'm new to the world of J2ME as well. I can tell you this: It is a hell of a lot of fun! Although J2ME is limited to what can be done, it's still a powerful language, and can be picked up very quickly if you have previous Java experience.
I would recommend checking out Sun's
Wireless Developer Homepage, which has some great articles/tutorials on the subject.
They've also got a nice introductory series on
Getting Started with MIDP, which will give you some solid foundation.
If you're looking on purchasing books, I would recommend any of the ones that have been mentioned here in the saloon. Daryl's book,
Java Development on PDAs: Building Applications for Pocket PC and Palm Devices, looks to be very interesting, as does
Jonathan Knudsen's book, Wireless Java: Developing with J2ME, Second Edition.
I'm currently reading John Muchow's book,
Core J2ME, which I find to be a fairly easy read. It's full of examples as well, so if you're like me, and learn by example, you'll find it a great addition to the book.