Why not just set up a channel on an IRC server or something? If really wanted you could include a java or PHP IRC client or something aswell. Then you don't really have any administrative worries, as long as you pick a decent server with good services like ChanServ and NickServ.
I'll second that, keeping an irc channel is very time consuming and can cause way too many problems. I was an operator on Dalnet in a channel with 500-600 averige daily users and it was HELL, that's why i quited after 3 years.