I've been trying to make an IRC chat client mod for YaBB for ages...
A friend sent me some Java code, I compiled it and signed it, yet it wouldn't connect to any IRC servers, not even localhost... couldn't be bothered to see what was wrong, got deleted.
Jpilot costs money, so if it was used in a mod, people would have to pay.
Eteria IRC requires you to sign the applet which takes time, and if you want a professional job costs money. It hasn't been developed in over a year and is buggy.
ConferenceRoom works great on my localhost IRC server, but only if the daemon I'm using is ConferenceRoom Server. It won't connect to any non-CR IRC servers, so that idea goes out the window.
So basically I haven't found a solution after trying lots of applets - apirc wouldn't even load in the browser window. I really want a chat applet that will connect to the IRC server my channel is on, but I doubt I'll find one... for free.