Well, actually its not ISO its OASIS..
But they have specified a load of standard XML components for common business entity, items and transaction data including address - something nobody has ever done the same way twice (although it does have address line subcomponents which is a cop-out).
Anyway its all usefully defined in the UBL spec and you can also see a class diagram for Address here.
I was thinking I could put together some modules that provide these classes in perl with methods to generate the XML or DOM structure as per the spec.
