If you find or hear about an open source J2ME/MIDP library or app, it tends to either be extremely out of date (from 2001 and designed for early MIDP1.0) or so bleeding edge that it doesn’t work on most devices. I was pleasantly suprised to find KVMJab, a Jabber library for MIDP 1.0 (though it should work fine with MIDP 2.0), alive and kicking. There is a new release of the source code just a few days old that is updated to work with Sun’s Wireless Toolkit v2.1. It looks like much of the source has not been touched since late 2000 or early 2001, but if it works, it works.