If you are a Firefox user:
You can install the "ChatZilla" addon and clicking in the link in Cairenn's post will open ChatZilla up to the WoWUIDev channel.
If you choose to install the "IRC Client 0.1" addon, the link in p3lim's post will work.
I use Firefox 13.0.1, and can check / add more addons through the "
Tools" menu, and clicking on the "
Add-ons" heading. After installation they will appear in your "Extensions" list.
PS: I'm a noob at this stuff, so I added that last bit. For other noobs like me.
(and, yes, that means that I will probably be "lurking" there now, too)