The SHA1 fingerprint is 7053F379C4EA34D0424FE9903FE2FE8E4856DD8E since some of you were asking us to post it.
We're using the same certificate as "www.livejournal.com" which is why -- depending on which client you use -- some of us are getting host/certificate mismatches. Some solutions are:
1. Accepting the cert, provided the sha1 fingerprint matches,
2. Accept the SSL "errors" or warnings,
3. (I've personally done this on Adium on a Mac but can't vouch for it working for you) change your Jabber server to "www.livejournal.com" from "livejournal.com".
I apologize for dropping this change on everyone without announcing it beforehand. We've been doing private beta testing for a few weeks now, simply because of the advantages that Tupshin outlined below. Recent changes to our codebase pushed our good ol' Djabber server over the edge, and we made the decision to switch Jabber servers a little early rather than try to waste cycles fixing the old server when we planned to cut over soon anyways.
The authentication problems that we've been having earlier today were due more to our database load rather than problems specific to the new Jabber server; lookups for your username/password and friends list currently are done against our database so when that was overloaded it prevented us from logging in or seeing our friends list. At this time, the service should be working well. If it isn't, please allow me to show you http://www.livejournal.com/support/.
Have a good weekend everyone!