Who doesn't want their apps to integrate with Facebook? the second most popular site worldwide, and most popular, bar none, in eight countries (according to Alexa)?
Or try this new tutorial from phpmaster.com. The author, Hari KT, introduces the guide:
Integrating with Facebook from PHP is easy with the help of Facebook’s PHP SDK and some HTTP libraries like Zend_Http_Client or PEAR HTTP_Request2. In this article I’ll show you how to get started using the Facebook PHP SDK. You’ll learn about the Facebook Graph API and create a Facebook application capable of updating your status message and uploading photos.
Hari runs through initial setup, explains, the Graph API, and provides a sample ('Hello Facebook') application. It looks pretty easy, and could lead to something supremely cool.