Here's a quote off of
http://www.telexperts.info/courier_shipping.htm
"DHL Express provides air service around the world. They are the only major courier that provides air freight service into Cuba (corporate deliveries only), Iran, Libya and North Korea, in addition to the other countries around the world."
I think my company tried the purolator thing as well, but most of the time the items were returned. DHL never had a problem.