If you don't want to install a seperate program for IRC, or can't (computer at work, school, etc), you can use the webinterface. It can be found here (click the yellow text balloon to enter a channel; you will be asked for a nickname and then join a channel) or go here for a login form with some more advanced options.
Login form
This form is quite simple actually. Just enter a nickname and the name of the channel you want to join.
Login form (advanced)
This form has a few more options. Your realname is displayed when another user 'whoises' you (/whois is an irc command that displays some more information about a person).
You don't need to supply a password, although if you registered your nickname you can enter the password here (so you won't have to use the /identify command later to idenitfy yourself to NickServ)
Format just selects the style/template of the main chat window.
The Port setting should not be changed or it won't work ;-)
The chat
The chat itself
The list of people currently in the chat. If you select a name, you can then select an option from the selection box and click the button to execute (Query will open a private message window for the selected person)
A list of the channels/query windows, click the name to go to another window
This is where you type your text (it can happen that this line isn't visible in Firefox, resizing the browser window should solve that)
Some buttons to add color or other markup to your text. Don't use it too much, and when using color, don't assume someone else has the same background color: white text on a white background isn't readable ;)
Help, Settings and Exit (closes the current chat window (channel or query), or the entire chat if it's the Status window)
