Here are a collection of Android tutorials and examples. If there is anything you would like to see or if there are questions please contact Digital Opium. The tutorials here will mostly cover native Android development and not mobile web applications built on HTML5 or hybrid approaches such as using PhoneGap.
Android development might be considered the easiest to start off with since it is built upon Java making tools and resources readily available online. You won’t need to purchase additional hardware for native development such as for the iOS.