Chris,
We have a full guide on
Facebook Open Graph Actions for Joomla
, and our example is for 'reading an article'. That should guide you through the process.
The one thing to note right now is that Facebook is changing the behavior of the actions that automatically post when a user 'consumes' content, like reading an article, watching a video, etc. They've temporarily removed that the action will post to a user's Timeline, but it does still post to the Ticker and other areas where it can be seen by a user's friends.
Hope that helps get you started,
Alex