those who are looking for the wordpress plugin to publish their post in facebook has been out now you can download via wordpress plugins directory ... http://wordpress.org/extend/plugins/facebook-wall-poster/ Note: it only works on Wordpress version 3.4.1 or higher Thanks
I can see how that'd be useful. Now that you have a base code set up, you should add support for Twitter and other popular social networks - make your plugin the best plugin for promoting new posts.