A couple weeks ago, I wrote about Pieter Michels’ Flash bridge for Facebook Connect that allows you to access Facebook Connect services from within a Flash application. This week, Adobe and Facebook decided to release an official version of an AS3 Facebook API, so now there’s an officially supported, feature complete way to access Facebook from a Flash-based Connect web site, a Facebook platform application, or a standalone AIR application.
There’s decent library documentation provided by Adobe, but I recommend just digging in and examining the sample code that’s been provided. It’ll give you a better overview of the primary classes you’ll be using and the initial steps you need to go through to authenticate and pass user data to and from Facebook.
Actionscript 3.0 Client for the Facebook Platform API
Flash for Facebook Overview and Code Samples
Facebook ActionScript API Documentation