Internet Relay Chat
Internet Relay Chat, or IRC, was around before your grandmother, and is used for multi-user chat. For generic information, use google or Wikipedia's IRC article.
IRC Clients
Again, Wikipedia has an excellent Comparison_of_IRC_clients, although there are several that are recommended by the irc community.
Windows
Linux
Mac
Connecting
Add to your network list, or simply connect to irc.case.edu. Most clients will allow you to list a choice of Handle/Nickname as well.
Once connected, use the command /join #notacon. This will connect you to the notacon channel, and you may start chatting. There are many other IRC commands. Use /help to view them.
Etiquette
There are numerous channels on the IRC server. We ask that you try to keep on topic for that channel.