J-Applet
J-applet 1.0.7.3 free download
http://www.softandco.com/internet/c/8/a/4802/j-applet.html
JAVirc
Java irc client
http://patrick.ducrot.free.fr/
JwIRC
JwIRC
http://www.jwirc.com/download.html
PjIRC
Pjirc is the best free java irc client available. it can be run as an applet or stand alone and it is fully opensource.
http://www.pjirc.com/