How an international piece of mail is addressed has a great impact on whether it is delivered on time, or delivered at all. The U.S. Postal Service requests that the last line of an international address be the country of destination in all caps (in English). Every country has its own unique addressing format and postal code that must also be used.
Helpful US Mail Resources
For more information on address formats rates, fees and custom declaration forms click on the following USPS site:
Mail Preparation Tips: http://pe.usps.com/text/pub51/pub51_024.html
USPS International Customs Forms: