Have you tried using the PHP SDK v3.0?
I have successfully upgraded one of my existing application from the PHP SDK v2.1.6 to the PHP SDK v3.0.
As expected, the migration is not as simple as what the sample code outlined in either the PHP SDK sample code or the Facebook Developer Blog.
Having said that, the migration is not that difficult. 🙂 This also forces me to go through the code in the PHP SDK v3.0 (as you just cannot get the job done by following the sample code).
Apparently, some thoughts have been made to give the PHP SDK a better design. I love the concept of having a base class with abstract methods and provide the default implementation by using PHP sessions.
Thanks the PHP SDK team for this nice piece of work!
I have started documenting and sharing my experience in upgrading Facebook application from the PHP SDK v2.x to v3.0.