Setup Facebook chat with Pidgin is simple.
In Pidgin follow the given procedure,
1. Accounts -> ADD will take you to the "Add Account" window
2. Set the following settings under the BASIC tab
Protocol : XMPP
Username : john.doe (if your facebook username is john.doe@facebook.com)
Domain : chat.facebook.com
Password : <your FB password>
3. Click "Add"
Now you are ready to go..gud luck
