J2ME for mobile devices have been around for quite awhile now. Unfortunately, the majority of applications have been arcade games. However, things may begin to change with the release of a J2ME version of Google Maps (check out his tour ). I downloaded it on my Nokia 7710 (used the generic J2ME version) and it surely was surely a treat!
The key to ease of use for Mobile devices boils down to ease of navigation. With the endless multitude of devices with different form factors cross-product with the endless ways of mashing up Google Maps, you are surely looking at a millions of markets of dozens.
So if there was ever a time to start mastering J2ME, then this absolutely has just got to be it! I made a couple of predictions at the beginning of the year that have mostly come to fruition.