kIRC is a totally free mobile application (client) for connecting to any IRC server. kIRC allows you to login to an IRC server, enter multiple channels at the same session, talk in the channels and with individuals and receive others' messages and easily keep the track of active channels and switch between them.
Skype IM Skype instant messaging java app for your nokia c3! do enjoy this app and remember
ICQ Mobile for Java The official ICQ application for Java phones lets you chat with Facebook friends directly from ICQ, enables you to update your status on the go and get status updates from ICQ and Facebook friends !