I don't know if this was an expected issue, or if you guys already know about it, since 1.4.2 is targetted at fixing the Facebook to XMPP transition; but the Facebook plugin is failing for several people today (Me included). I guess http://trac.adium.im/ticket/14593 was the first report.
Maybe a blog post should be made, to inform people how to do the XMPP transition manually, until 1.4.2 comes along, to expose the problem? David Munch