http://www.magentocommerce.com/magento-connect/beetailer-facebook-integration.html

Beetailer. Your Online store on Facebook.

Beetailer integrates your Magento store with Facebook, Twitter and Google+, helping you to increase your sales and to reach more customers. It provides deep integration with Magento, including the shopping cart API, so customers can shop inside Facebook but they check out in your regular store. Beetailer is in use by thousands of ecommerce stores reaching over 50 Million fans.

This extension requires free registration on http://www.beetailer.com. Setup takes minutes and does not require any coding.

Features

Integrates with your existing store

No need to re-enter or migrate your product data. Beetailer will use your current catalog and stock information and keep it synchronized automatically.