The Force.com Toolkit for Facebook is a free set of tools and services that enables developers to harness the power of the Facebook and Force.com platforms to build business applications for Facebook.
The Force.com Toolkit for Facebook gives you direct access to the Facebook APIs from within Apex Code, letting you create new social graph applications and user experiences that connect directly to Force.com’s Sites, database, integration, logic, and Visualforce user interface capabilities. Now, you can tap into Facebook's social graph from the enterprise cloud.
If you're ready to start coding, check out the following resources:
Recording of a Dreamforce 2011 session showing how to use the Force.com Toolkit for Facebook to build a social application on Force.com.
Check out the following resources from Facebook's developer portal: