Point your irc client at deathray, port 6668. You'll be auto-joined to a '#bitlbee', and type 'help'.
Quick starter for MSN:
In '#bitlbee', say:
account add msn firstname.lastname@example.org password account on 0
It'll connect then, and you'll see all your online people join the channel. You can talk to them in two ways, by saying 'nick: message' in the channel, or by private messaging them.