Facebook commenting integration like Mashable

Hey guys,
I just was just wanted to know if anybody has got the commenting facebook plugin on your blog.

What im really wanting to find out is, how does mashable allow users to comment normally or allow them to sign in to facebook and comment on that blog post.

If you see at the bottom of a post by mashable they have an option what says "To leave a comment on this story, please log in with Facebook / Twitter"

Does anybody know how to add this function to their blog etc?
Any ideas?

Cheers
Cloudy

Check this out: http://developers.facebook.com/docs/reference/plugins/login/

Also check out the other plugins: http://developers.facebook.com/docs/plugins/

Facebook has made it very easy to integrate it into websites/blog.

Hopefully you'll find this helpful!