Whenever an international parcel delivery order is made you'll be requested to fill out and attach a pro forma invoice (pdf). This is to allow the recipient's local customs authority to determine what import duty is due and if the goods are legally allowed to be imported without restriction.
At this point the recipient will become responsible for any duty or fees due. They then can arrange that payment to be made.
This aspect can be very complicated as the rates and applicable items are different for each country outside of the EU. We advise you to work with the recipient and establish the rate of duty before you arrange a courier to collect your parcel or parcels.
As of 15th June 2012 our terms and conditions state (3.5) state that 'it is the responsibility of The Customer to submit all papers required for the customs clearance. The Customer shall pay the costs for customs clearance.' We do, however, suggest that you re-check the terms and conditions again before you book your international parcel delivery.