login information Magento

$from_email = Mage::getStoreConfig('trans_email/ident_general/email');
 $from_name = Mage::getStoreConfig('trans_email/ident_general/name');


$customerId=0;
if($customer = Mage::getSingleton('customer/session')->isLoggedIn()) { $customerData = Mage::getSingleton('customer/session')->getCustomer();  
echo  $customerId=$customerData->getId();
}