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

Question

I want to add the following buttons to my website for providing users with option to login using more services like Google, Facebook etc.

Please answer the following questions:

1. How can I add various services like this free of cost? (Please note that I do not want to use any paid service like Janrain and )
2. How can I store user information of the user (like email, phone no.) that are stored in the accounts to my database?
3. Please provide any links/libraries that can be used.

I appreciate any other information that you can provide.

Thank you!

Answer 1

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.