If anyone is rocking Mac OS or iPhone/iPod, take a look at Delivery Status. A very nice program (a widget in Mac OS) to track packages from pretty much every carrier as well as some shops like Amazon without having to specify the carrier.

You can name each delivery you're tracking and also set a number of options including how often to update the status. You can also sync the details with the developer's site which then allows you to pull back the info onto your other devices.

I've known about it for a long time, but just started using it today mostly because of the discussion we've had here. Very handy when you have a handful of things arriving. Especially if they're not arriving at your current location - I have to know when to drive down to my US mailbox to pick up a batch of stuff for instance.