1. A method of sorting, in accordance with a predetermined set of criteria, an international mail piece exhibiting at least a destination address field and an indication as to a level of delivery service requested, the method comprising the steps of: capturing at least one image from a surface of the mail piece and storing the at least one image in computer memory, the at least one image including at least a destination address field image corresponding to the destination address field on the mail piece; maintaining international-mail-services postage data relating required postage rates to data indicative of at least one predetermined mail-piece characteristic selected from a set of mail-piece characteristics including (i) international destination, (ii) mail-piece type, (iii) mail-piece weight, (iv) mail-piece dimensions and (v) service-type requested; resolving the at least one captured image associated with the mail piece to produce a resolved data set associated with the mail piece and indicative of at least one of (i) the identity of any international destination indicated in the destination address field, (ii) whether any postage amount was paid, (iii) the amount of any postage paid, (iv) the mail-piece type and (v) the service-type requested; consulting the international-mail-services postage data and comparing the resolved data set to the international-mail-services postage data; and rendering a determination, based on the comparison between the resolved data set associated with the mail piece and the international-mail-services postage data, as to whether any postage indicated as paid by data within the resolved data set is sufficient to further process the mail piece in accordance with the level of delivery service requested.