This document provides an overview of application development for Windows Phone 7. It discusses the app model, user interface model, software architecture, hardware foundation, and cloud integration services. The app model focuses on the user experience and allows apps to integrate with key Microsoft services like Bing, notifications, and location through common frameworks. The UI model organizes apps using pages and sessions. The software architecture includes frameworks for Silverlight, XNA, and the common language runtime. Hardware specifications include touchscreens, sensors, cameras, and performance requirements. Cloud services enable location, notifications, and accessing existing web services from apps.