Adobe and Facebook announced a joint effort to enable developers to create Facebook applications using the Adobe Flash Platform and Facebook platform. New ActionScript 3.0 Client Library for Facebook Platform API is released and is fully supported by Facebook and Adobe.
You can find excellent documentation on how to build Facebook applications and more details at this URL http://www.adobe.com/go/facebook/
ActionScript 3 Library http://code.google.com/p/facebook-actionscript-api/
Adobe Rocks 🙂