This document compares coding and tools for developing apps on the iPhone versus Windows Phone 7. It provides a step-by-step example of creating a simple "hello world" master-detail app on the iPhone using Xcode and Objective-C. It then ports the same example to Windows Phone 7 to show differences between the two platforms. The document aims to provide an unbiased comparison for developers to evaluate the strengths and weaknesses of each mobile development environment.