This document compares Appcelerator Titanium and PhoneGap for cross-platform mobile app development. Appcelerator allows developing native mobile apps using JavaScript while PhoneGap uses HTML and JavaScript within a native container. Appcelerator offers better performance since it produces truly native apps, while PhoneGap apps have a wrapper interface. The document provides an overview of what is needed to start developing with Appcelerator and links to its API documentation and wiki for learning resources.