This is the fourth video in the series of videos provided by Google on Android programming.
00:25 Dianes ringtone app
01:08 App to create a shortcut to anything on the system
01:36 Replacing the home screen (End at 02:17)
This video shows that all applications created on the Android platform are equal. Even though I have not done any iPhone development, I believe applications written for iPhone do not have access to everything the way Android applications do. So this is a positive for Android development.
In this video we see how to a custom application can change the ringtone on an Android phone, how another application can create shortcuts to anything on the phone, and how we can also change the 'Home' application.