The IRC is a place for you to socialize with other people outside of the wiki chat. You can talk with others and talk about things unrelated to Kingdom Hearts, though things having to do with Kingdom Hearts are encouraged too.
Connecting to the IRCEdit
You can connect to the IRC using freenode's webchat client. Once you are there, you can type in your username into the box and type in the captcha. Alternatively, if you already have a client, you can type in /j #kh-fanon.
The IRC rules are basically like the wiki chat rules, found here.