This is one of the many examples of interesting Google Maps: http://maps.google.com/ implementations. Package Mapper: http://packagemapper.com/ takes your FedEx, UPS, or USPS package tracking number and maps your package's route for you. Registering and signing in will allow you to save multiple package routes into your package list, allowing you to display multiple package routes on a single map.

Give it a try the next time you expect a shipment!