IOS SDK
The Software Development Kit for iPhone OS was announced at the iPhone Software Roadmap event on March 6, 2008. The SDK allows developers running Mac OS X 10.5.4 or higher on an Intel Mac to create applications using Xcode that will natively run on the iPhone, iPod Touch and iPad. A beta version was released after the event and a final version was released in July 2008 alongside the iPhone 3G. As of September 2012, the latest iOS SDK is for iOS 6.0.
This major Roadmap event (coupled with a large distribution program for 3rd-party developers), later became known as the iPhone Developer Program, which currently offers two distribution tracks for 3rd-party developers: Standard, and Enterprise.
Applications distributed through the standard program can be sold exclusively through the iTunes Store on Mac and Windows, or on the App Store on the iPhone, iPod Touch, and iPad. Developers who publish their applications on the App Store will receive 70 percent of sales revenue, and will not have to pay any distribution costs for the application. However, an annual fee is required to use the iPhone SDK and upload applications to the store.
Applications developed through the enterprise program, officially the "iOS Developer Enterprise Program" (iDEP), are exclusively for institutional use and do not get published on the App Store. This allows corporations, non-profits and government agencies to develop proprietary "in-house" applications not for public release. The enterprise program was updated September 14, 2010, to allow any organization with a DUNS number to join. Prior to this date, only organizations with 500 or more employees could join the enterprise program.
To run an application on the iPhone, the application must be signed. This signed certificate is only granted by Apple after the developer has first developed the software through either the US$99/year Standard package or the US$299/year Enterprise package with the iOS SDK.
Read more about this topic: App Store (i OS)