OpenID for websites similar to the one at stackoverflow

Possible Duplicate:
How do you enable customers use their openid on your website, just like stackoverflow?

Duplicate of:

How do you enable customers use their openid on your website, just like stackoverflow?

I need to create a login as the one shown at stackoverflow, the openid, google,yahoo etc. how do I get about doing the same.

From stackoverflow

• class for PHP:

  http://openidenabled.com/php-openid/

• Please read this question.

• http://code.google.com/p/dotnetopenid/

  If you're using .NET

• Google API

• I might point out that stack overflow also uses the openid-selector lib

• Stack Overflow uses this library for the smoking hot javascript interface: http://code.google.com/p/openid-selector/

  You can see the code they're using at http://sstatic.net/so/Js/third-party/openid-jquery.js

• I used RPXNow on one of my sites. They handle the UI for you if that's what you want.