With a rich set of over 1,000 new APIs, iPhone SDK for iPhone OS 3.0 provides an amazing range of technologies to enhance the functionality of iPhone and iPod touch applications. New APIs also provide support for applications to communicate with hardware accessories attached to iPhone or iPod touch. Some of the new functionality includes allowing users to purchase content or services from applications using the Store Kit framework, peer-to-peer interactions in the Game Kit, allowing applications to communicate with "Made for iPod" hardware accessories attached to iPhone or iPod touch with the External Accessory framework, and more. This book will appeal to both current developers needing to understand and update their apps to the iPhone OS 3.0 and for those developers just starting out who need a complete tutorial and reference to the iPhone SDK 3.