Windows users use mIRC (www.mirc.com) and other users use xIRC or BitchX (www.bitchx.org) to connect to an IRC server.
Once connected to a server people can message each other in private or in public channels.
I was on DragonzKeep IRC server and I met this great girl in the server chat channel.
Clients connect to a specified server which is part of a collection of servers known as an IRC network. If a client is to send a message to a user on a different server within the same IRC network, the message is relayed between the servers and then to the other client.
IRC is a text only means of communication, non-text communications or files are sent via IRC's file transfer protocol, known as DCC.
Unlike other chat protocols, IRC does not require you to have an account that you sign in with, but most IRC networks offer you the ability to reserve your nickname.
Common IRC clients include X-Chat, mIRC, Irssi and BitchX.
***loading .ircr version 2.9.5+Cr17f+F08
***users on #channel: @the_fist, @00zemeister
> the_fist G07 4 5urpr153 4 U