Alternatively, you can install Quassel IRC (or any other IRC client that blows your mind) from ubuntu's Add/Remove app.
When you fire it up, it'll prompt you for a default server, and it's pretty easy to fill in. Server will be
irc.susans.org and the port number 6667.
Fill those in, save & connect to the server.
Once connected, the server will dump a few paragraphs of text including the names of channels to join and a few notes on appropriate use of chat, obtaining help, etc.
Pick a channel that suits your interest and join it by typing "/join #TSTalk" without the quotes (if #TSTalk happened to be the channel of your choosing).
