If you've been thinking about hooking up your application's authentication to the Facebook Connect system that Facebook has to offer but weren't sure where to begin, take a look at this new tutorial from NETTUTS.com for a good introductory guide.
Lately, there’s been quite a fuzz about lazy registration. It turns out that the less the user has to think, the higher the conversion rates are! What a thought! If everybody seems to have a Facebook profile, why not add a one-click user registration? I’ll show you how to do that today.
The complete details are here - everything from the SQL to create the MySQL backend tables to screenshots on how to set up the Facebook application to the actual code to make the authentication work. There's even a bit on extended permissions and how to push a message to the user's wall once they've approved the application.