MobJab Mobile Messenger MIDP 2.0 - Introducing MobJab your very own Instant Messaging and Presence (IMPS) client for FREE. No need to send expensive SMSes to your freinds. Just activate GPRS on your Mobile Phone and you are always Online. You just need to create your MobJab ID once and start chatting with your freinds from your mobile. MobJab would work on all Mobile Handsets, PDAs and Smart Phones based on Symbian or Windows Mobile OS. MobJab supports J2ME with MIDP version 2.0 and CLDC version 1.1.
WonderChat International platform for mobile phone users to Chat and connect with each other online
BlueBuddy BlueBuddy - BlueBuddy is a J2ME application for Java-enabled mobile phones with JSR-82(bluetooth), which users (up to 8) can use to chat with other users through bluetooth. The main benefit is there is no chatting fees, however, it's only capable for short range communication (about 10m for mobile phones)