What Is IRC?
IRC is Internet Relay Chat. It is a way for people to communicate in real time with people from across the globe.
IRC consists of several different Networks comprising of Servers which allow people to connect to IRC. On the Networks there are Channels, where Users can come together to discuss about things that the Channel is suited for, or dedicated to. Users are identified on IRC by their Nickname.
Depending on whether Networks utilise IRC Services, Nicknames and Channel names can be registered so that only the "owner" can use it.
Channel Operators (ops) are the "bosses" in a Channel, and they have the power of enforcing certain things like the removal of Users from said Channel, whether temporarily (kicking) or permanently (banning).
IRC Operators (ircops, opers) and Administrators have the same kind of power, but on a Server (local) or Network (global) scale and can restrict a User's access to a Server or the Network.
You can connect to IRC by using a client such as mIRC (Windows), or IrcII (Unix). A list of IRC clients can be found here. Many Networks also offer the possibility of connecting to the Network via a web-based Java chat client. Whilst handy, a seperate IRC client is still recommended over a web-based option.
For more detailed information about IRC and how to chat please go to the IRC Help site.