Seemed to be working but all of the sudden it starting making my FireFox browser refresh indefinately. I noticed that clicking Log Out didn't log me out, and then the FB Connect button stopped responding. Now it just works when it decides to but most of the time it doesn't.
This is the error I see in the FireFox console:
FB.login() called before calling FB.init().
Not sure what's going on but seems very buggy.