WordPress Facebook Like and Send Button plugin by Pasquale Puzio allows the option to add the Facebook Like and Send Button at the top of your posts or at the bottom. This setting is available on the “Reading” page of your settings in your WordPress admin panel. It will default to the bottom of the post.
Adding a Facebook Like and Send Button gives your visitors the option to like or send to their friends your posts on Facebook. This will allow their friends to find your post as well and spread your content to lots of new people.
Download and info: http://wordpress.org/extend/plugins/facebook-like-and-send-button/