Based on WPBook ( http://wordpress.org/extend/plugins/wbook/ ), WPBook Lite enables cross-posting of blog items to Facebook, and import of comments
Copy the entire wpbook-lite directory into your wordpress plugins folder, /wp-content/plugins/
You should have a directory structure like this: /wp-content/plugins/wpbook-lite/wpbook_lite.php /wp-content/plugins/wpbook-lite/client/
Set up a New Application at http://www.facebook.com/developers/, obtaining a secret and API key.
Set the application type to "website"
Login to WordPress Admin and activate the plugin
Using the WPBook menu, (Dashboard->Settings->WPBook) fill in the appropriate information including Facebook application secret and app ID, as well as your application canvas url.