libircclient is a small but powerful library, which implements client-server IRC protocol. It has all features needed to create your own IRC client or bot, including multi-threading support, sync and async interfaces, CTCP/DCC support, colors, SSL connections and so on.
Java Instant Message (IM) Library, Client and Tools. Flexible framework to design your own. AIM, ICQ, Yahoo, MSN, Jabber, SMS, Nate, GoogleTalk. GUI, spell checking and more. Includes a web interface for remote/cell access. Mac, Win, Linux friendly
The aim of Howdy is to provide a simple, easy-to-use method of text-based communication over TCP/IP through a simple graphical userinterface. Both the server and the client are small and run on all platforms supporting Java.