countryCode looks like US in magento

// $countryCode looks like "US"

$customer = Mage::getSingleton('customer/session')->getCustomer();

$countryCode = $customer->getDefaultBillingAddress()->getCountry();

// looks like "United States"

$country = Mage::getModel('directory/country')->loadByCode($countryCode);

echo $country->getName();

// $regionCode looks like "UP"

$customer = Mage::getSingleton('customer/session')->getCustomer();

$regionCode = $customer->getDefaultBillingAddress()->getRegioncode();