How to login with facebook by using api

PHP
1

hello sir,
i want to post on facebook through my website by using the API how i use the api of the facebook,twitter,photobucket ect
plse tell me the php code and what are the resources required.

please tell solution as soon as possible its urgent.

2

Did you mean you want users to be able to login to your
site using their facebook id’s?

3

This article can help you

http://developers.facebook.com/docs/authentication/