I want to Add New Shipping Carrier in the Shipping ->Shipping and Tracking Information->Drop-down. so how I can I add extra shipping carriers.
You can add addition carrier option in below file
Go to Line 70 , Add below line before
return $carriers; in getCarriers() Function
$carriers['My Custom Carrier'] = Mage::helper('sales')->__('My Custom Carrier');
My Custom Carrier with your carrier name.