Programming the iPhone user experience

The book Programming the iPhone user experience provides you with a hands-on, example-driven tour of Apple's user interface toolkit, UIKit, and some common design patterns for creating gestural interfaces and multi-touch navigation for the iPhone and iPod Touch. You'll learn how to build applications with Apple's Cocoa Touch frameworks that put the needs of mobile users front and center. The paper version costs less than 35$, including the eBook is less than 39$.