Just in time for your last minute holiday shopping, Amazon is adding push notifications for shipping and delivery to its Android app. From the app settings, you can select to receive push notifications from the app -- both when packages are shipped and daily when there are "lightning deals" available that you may be interested in. Considering most of us will receive an Email notification (and possibly a Google Now card) at the same time as this, it seems a bit redundant to have another app notifying you. But if you're doing a lot of shopping on Amazon, its nice to get the info straight from the source.
The Amazon app is already very useful when it comes to tracking and managing purchases, so this just adds to the experience. You can grab a download of the latest version at the Play Store link above.