Just a quick snippet of code that will return you the Country Name based on a country code, e.g if you’re looking at the Order model getting the country_id of GB, however you need United Kingdom, the following code can be used:

[code]Mage::app()->getLocale()->getCountryTranslation($country_id);[/code]

Simply pass in your country id value (e.g GB) and Magento will return the full country name.