title: Anyone know of a good tutorial for Facebook authentication?
body: <p>I'm linking my app to Facebook, and would like people to log in with their Facebook account, but I can't figure out how to do this.  I had read up on Facebook Connect, but it seems that that's not used any more - but every tutorial I can find seems to refer to it.  When I try to follow them, it doesn't work, because the interface has changed.</p>
  <p>So, can anyone direct me to a tutorial or guide to doing this the new way?</p>
  <p>Basically, what I want to do is this:</p>
  <blockquote>
  <p>A user who is signed into Facebook and comes to my webpage is automatically logged in to my app (with the usual Facebook 'granting permission' windows etc), or can sign in with their Facebook account if they're not already logged in.</p>
  <p>I then want to use Facebook to link users with their friends who are also registered on my site, so they can share things.</p>
  <p>I would also like to have access to Facebook comments made on wall posts from my site - so the comment stream for a particular post can be seen on my site as well as on Facebook, and comments can be made on either.</p>
  </blockquote>
  <p>If anyone can point me in the right direction (or even tell me what I should be typing in to Google!) I'd be very grateful.</p>
  <p>Thanks.</p>