Howdy
The Lovely Evil Elena took this pic for me when I was figuring out how to get on.
It shows the server she recommended with the big red arrow (at least for the L&C channels), and then after you pick a nickname, click connect to IRC. Then it'll take forever to connect (if it's my computer <g>) and a join channel screen will come up...the one I go to is #loisclark so I type
'#loisclark password'...the L&C ones are password protected.
Also go here for more info
http://lcfanfic.com/faq_archive.html#whatisirc The Archive there has plenty of info on it, plus there are people way more IRC coordinated than I am here <g>.
Jen