InterShipper API (Built into the .Net shopping cart)
This feature allows you to seamlessly integrate with the InterShipper rate service. You can provide real-time, accurate, shipping rates to your customers:
Canada Post (Canadian Postal Service)*
DHL Worldwide Express*
USPS (United States Postal Service)
UPS (United Parcel Service)
FedEx (Federal Express)
Intershipper is only required for Canada Post and DHL. The shopping cart itself supports USPS, UPS, and FedEx.