I'm old-school. No, really. Even in this day and age of graphical desktops (and, hey, I could hot-desk X11 sessions at home with my smartcard if I really wanted to) I keep an ssh tunnel open to a friendly server, with GNU screen and irssi in there. And that's my Instant Messaging setup. Kopete is nice (er .. usually, although I haven't managed to get it to do anything useful in Solaris yet), but misses the always-on functionality of screen.
But irssi is an IRC client, and the FSFE uses Jabber for much of its communication. There's #fsfeurope on Freenode, but other than that .. the Fellowship page on communications channels is a good resource. I briefly mucked about with irssi-xmpp plugin on FreeBSD, but couldn't get any useful functionality out of it. It also seemed quite complicated to set up right.
Enter BitlBee, which bridges some other IM clients to IRC, by acting as an IRC server locally. This is one of the rare times that I've rushed up to one of the developers of an application and gushed "I love your app! It improves my life!" Well, I've met Jelmer enough times at various conferences, I think I can take liberties like that :) The FreeBSD port installs flawlessly, has a few issues when running in jails and segfaults on OTR requests, but those are technicalities: the functionality and the level of guidance given by BitlBee (the in-channel help is excellent) makes it dead simple to set up and use. And as a consequence, I now have 4 IRC channels (#ebn and #kde4-solaris among them) and 3 Jabber groupchats open (including the Fellowship channel), in screen, on my server, where I can enjoy years of uptime and uninterrupted conversation.
Thanks Jelmer, Maurits and Wilmer.