If you are like me and want to track multiple packages from any Postal System or currier co. all at the same time this is the App I have been using for the last couple of years. It's called "parcel", and it tracks everything and sends me a pop up notice every time the package is scanned or moves.
Mine is an ipad app, and there is an iPhone version, I don't know about other devices. It's free, and lets you track up to three parcels. I paid an extra $1.99 for the deluxe and got a few extras like tracking up to thirty parcels with instant notifications.
It pretty much supports every postal system and currier in the world, and makes multi-tracking a one glance operation. No need to keep inputting tracking numbers.
Ok, I have been trying out the free version of the "parcel" tracking app for iPhone for two weeks now. I like it, but it seems like 90% of the time I get an error message saying "Sorry, Unable to update the data. Please check your internet connection". Is this a frequent issue with this app? The two tracking numbers I have entered right now are set to USPS for tracking, so I know it's not an issue trying to pull tracking data from China Post or HK Post websites. I would consider purchasing this app if I didn't get this error so frequently.