Push notifications is a constantly-open IP connection used to forward notifications from the servers of third party applications to your iOS device. They are used as an alternative to "always running" applications, and allow your device to receive notifications from a specific app even when it is not running. If you have ever received an SMS on your iPhone, then you'll aready know what push notifications looks like. They are essentially a message box that consists of a title, a message, and both a "Close" button and an "Action" button. The "Action" button can be defined by your code, in both appearance and the underlying action and data that you want to be passed to your application when that button is pushed.
You will need to register for an account with Urban Airship at https://go.urbanairship.com/accounts/register/. Once you have registered and verified your account via the email link sent to you from Urban Airship, you...