Forgive me for the stupid question but I have no idea what it is and how to use it. Can someone please explain

Is it like msn?

Internet Relay Chat, a precursor of sorts to modern instant messaging, although it's still pretty popular. It's a little harder to use than normal IM, you usually need a special kind of client and need to know some basic commands.

Ok cool. What are the benefits of using it over other IM programs

Well, it's universal, so you can be sure that what appears on your end will look the same to everyone else. Also, on Linux, you can use it through the Terminal, which is nice if you need help with something and have no access to any other form of IM.

It's more of a chatroom than IM (I suppose you could say it's like a group chat on MSN, but that's also like a chatroom).

IRC is a lot more suitable for multi-user chat than IM, since you don't need everyone on MSN or AIM to use it. IRC also allows you (depending on the network) to create multiple channels. On most networks, channels can be "registered" so they belong to you as long as they're registered and you enter the room regularly (they usually time out after 14 days of you not entering them but it can be different).

I think IPS Company Forums needs a chat again, I tend to get bored.

I think if they added some for a quick chat that would be great

Ah the good ol' IPS Live Chat - that would be nice to have that back someday.

Try this, Matt: http://www.irchelp.org/