protected function _prepareCollection()
{
$collection = Mage::getResourceModel('customer/customer_collection')->addNameToSelect()->addAttributeToSelect('email')->addAttributeToSelect('created_at')->addAttributeToSelect('group_id')->joinAttribute('billing_postcode', 'customer_address/postcode', 'default_billing', null, 'left')->joinAttribute('billing_city', 'customer_address/city', 'default_billing', null, 'left')->joinAttribute('billing_telephone', 'customer_address/telephone', 'default_billing', null, 'left')->joinAttribute('billing_region', 'customer_address/region', 'default_billing', null, 'left')->joinAttribute('billing_country_id', 'customer_address/country_id', 'default_billing', null, 'left');
$this->setCollection($collection);
return parent::_prepareCollection();
}
