Creating Facebook Application

Login the facebook website with your facebook account details.

Create an Application

Click the following link to create new application http://developers.facebook.com/setup/

Developer Dashboard

Click the 'Developer dashboard' link to enter your application page.

API Credentials

After given your Site name, Site URL you will get the following page. You can get 'API Key' and 'Application secret' from this page for your application

Site Domain Setup

In the following window, select 'website' tab from left and give proper Site URL and Site Domain