If you are writing a custom module, and you want it to be accessed only by admins, then you possibly need the following code in your controller.
//get the admin session Mage::getSingleton('core/session', array('name'=>'adminhtml')); //verify if the user is logged in to the backend if(Mage::getSingleton('admin/session')->isLoggedIn()){ echo "Admin Logged in"; } else { echo "You need to be logged in as an admin."; }