Bitlbee is an open source IRC project. It creates a gateway between irc and popular IM protocols such as msn, jabber, and oscar. You connect to a bitlbee server and you can add accounts such as Facebook, twitter, msn, icq, aol, yahoo, gtalk, etc etc. They all populate a userlist, and when you pm them it acts as a standard message sent through any IM client. The joy of this is you have all your s*** in one place, and if you already use IRC it's even better. It's also a lot faster to connect all your stuff, and your only limited to your IRC clients limitations. If you use mIRC + NNS you know possibilites are endless with this kind of a setup. You can also do group chats etc.
Anyways, I have my own private bitlbee server, and if you're interested in using it you can PM me. You can alternatively use the public servers on bitlbee.org, which may be less reliable and secure.