The Core Location framework in the iOS SDK is an asynchronous API that uses delegation to report location information from the iOS device. Along with location information, Core Location also reports the Heading information (Heading here implies the direction in which a device is pointed), as well as allowing you to define geographic regions and monitor when you cross those regional boundaries.
Core Location implements all the three methods of location detection: GPS, Wi-Fi, and Cell Tower Triangulation. The developer can control location detection by only specifying the accuracy needed. Core Location then decides internally on which approach to use for actual location detection.
When creating an application that uses the Core Location framework, you need to first add it to your project in Xcode and include the<CoreLocation/Corelocation.h> header files in your .m or .h file.
The new iOS SDK 5 and Xcode 4.2 includes a nifty location simulation and...