Apple's Game Changer, Downloading Now

As the Apple App Store evolves, it is changing the goals of developers, bolstering sales of iPhones and causing competitors to overhaul their product lines. Thanks in large part to the iPhone, introduced in 2007, and the App Store, which opened its doors last year, smartphones have become the Swiss Army knives of the digital age. They provide a staggering arsenal of functions and tools at the swipe of a finger: e-mail and text messaging, video and photography, maps and turn-by-turn navigation, media and books, music and games, mobile shopping, and even wireless keys that remotely unlock cars.