How to add Social login services from Google, Facebook, Yahoo etc. to my website?

You’ll be using the APIs of the respective services (Google, Facebook, Twitter) or may be OpenID if you plan to add that as well. Some links: http://code.google.com/apis/accounts/docs/OpenID.html https://developers.facebook.com/docs/authentication/ http://dev.twitter.com/pages/auth http://openid.net/add-openid/ Also take a look here. There are several similar questions already present on SO, check the related questions on the right.