mig33 Mig33 is the largest mobile chat community, connecting millions of mobile friends all around the world
Bluehoo Make new social connections with people around you!
Slick Slick is instant messenger application for Symbian mobile devices supporting ICQ, Yahoo, AIM (more to be added later)
phIRC PhIRC is considered as beta as many things are missing I'd like it to have
netomat Hub Read news, update blogs, share images, and hold online chats from your phone and your PC using this free service!
Yeigo Mobile VoIP. GoogleTalk, MSN, Yahoo!, AIM, ICQ and Jabber instant messaging
T2Me (Push-to-Talk) for Series 60 A Push2Talk system which turns your cell phone into a virtual Walkie-Talkie; It enables voice messaging with other T2Me users simply by typing in their number and a button-push