Hello,
Such functionality is not implemented in Kentico
CMS yet. However, since Kentico CMS is standard ASP.NET application, you can develop such feature on your own. You will basically use the Faceboook API to integrate it within the Kentico CMS.
You might find helpful the following link: http://developers.facebook.com/
You can also try to search on the Internet for possible solutions.
Best regards
Ondrej Vasil