Is this in development?
I would like to see this feature as well.
This is a wonderful and useful app. Adding this feature though would take it to a new level of customer satisfaction.
Sometimes, the carrier is not known when I receive the tracking number. It would be so helpful to have the app automatically match it up to the appropriate carrier.
Even if it's not practical at this time to add this feature, perhaps you could benefit from users doing the matching in the app and cultivating that into a master list.