Facebook just announced their first official plugin for WordPress:
Starting today WordPress publishers can easily integrate Facebook features, such as social publishing and mentions, through the new Facebook for WordPress plugin.
The plugin was built by Facebook engineers in collaboration with open source partners, and makes it simple for anyone to make their WordPress site more social – no coding required. The plugin will also work on mobile and support internationalization.
The plugin is built-in to our WordPress.com VIP platform and can be seamlessly enabled on any VIP site. It’s also available for download for self-hosted WordPress sites as well.