What is IRC?
"Internet Relay Chat (IRC) is a form of real-time Internet text messaging (chat) or synchronous conferencing. It is mainly designed for group communication in discussion forums, called channels, but also allows one-to-one communication via private message as well as chat and data transfers via Direct Client-to-Client." - Wikipedia
I spend a lot of time on the freenode irc network, helping the FLOSS community.
freenode is not a general chat network, but one whose goals seek to enhance communication between the many FLOSS project members.
If you're interested in joining us on freenode, you'll need an irc client to access an irc network (such as freenode). Once you decide on a client, please visit http://freenode.net/using_the_network.shtml for instructions on how to connect to freenode and a bit of an technical overview.
