comment box from wp.com for my self hosted blog

Hello,

How can I use the same comment box used on wp.com blogs? I want to have the same options to post as anonymous, login with twitter/facebook/wordpress and that comments are stored locally.

If it’s not just a hack, is there a plugin to make it work that way? So far I’m using a Facebook integration, but I end up with 2 comment boxes, one for facebook and another one the original from WP.