If you were going to use IRC, I would take the route of a normal irc server and a lightweight applet like <a href=
http://www.majik3d.org/~namhas/jicra/>jicra</a> for chat. You could hack either the server or a client to do logging & stuff. IRCG looks like they're making things way more complicated than they need to be.
(If anyone is interested in improving jicra, let me know; I've started with some cosmetic enhancements.)
