Unlike Google’s Android and BlackBerry, the iPhone takes a step backwards to use an old programming language technology, namely Objective-C . During the late 1980s to mid 1990s, there was much activity in object-oriented programming languages, with many versions of C++ from different vendors (with different language features and implementation), as well as a host of object-oriented languages such as Objective-C, Eiffel, Object Pascal, etc. Objective-C is a Smalltalk like extension to C with limited commercial usage (Apple’s Mac OS X and iPhone OS). Despite this, Objective-C usage is broad, when one considers that the iPhone has the greatest number of available applications (and still growing).
As with the other Smartphones, the iPhone/Apple maintain a detailed developer web page: http://developer.apple.com/iphone/. You need to sign up as a free Registeredd iPhone Developer at: http://developer.apple.com/iphone/sdk1/. From a development perspective, registered users can download the iPhone SDK 3.1.2 which includes the Xcode IDE, the iPhone Simulator, and an additional tool suite (http://developer.apple.com/iphone/login.action). Clearly, in addition to learning about programming on a hand-help application, for the iPhone, you will need to learn a new programming language (Objective-C) and associated I DE (XCode see http://developer.apple.com/tools/xcode/).