Drupal has a huge number of modules, some active and some dead, relating to Facebook. I'm going to take the advice of @madmatter23 and use the well done FBOuath plugin, which keeps track of your auth tokens, provides a nice, simple interface to the GraphAPI, and allows you to easily transform an FB user into a drupal user.
Here are two links to get started:
When you start building your own wrappers for Graph API calls, be sure to do it in
fboauth.api.php, as the latter script isn't called by anything. Or else you'll be like me yesterday and be all 'hurr durr why isn't it working?' for three hours.
My use case was wanting to have a login with facebook button (FB Connect) and also to show the number of users who were using the FB app. FBOauth took care of the first part, and I used the Facepile plugin to show how many friends were running the app (you'll have to remove the part about the website and just put in the app id in the url call to Facebook).
But most importantly, here is the most important link you will ever need when doing Graph API development!!!!!!11