Can you suggest some working example of it? I tried Authlogic and Devise withous success.
If you're going to use Facebooker 2, you'll have to upgrade your Rails framework to 3.0. Ayeah Games just went through the process for the game FanSwarm (on Facebook). This is no easy task, but the blog post may give you some insight.
http://www.ayeahgames.com/blog/bid/55099/The-Horror-Upgrading-to-Rails-3