The UCC has a jabber server running for member communications, as well as for monitoring things such as the doors.
You can create an account on the jabber server ucc.asn.au, your username does not have to be the same as your UCC username. You will need a Jabber client such as Gaim, Gossip, iChat, Adium or Trillian Pro (?). There should be one available on every UCC machine.
The UCC jabber server is now configured for inter-server communications, so you should be able to chat with your friends on other Jabber servers (including Google Talk).