Apple released a major update to its developer tool XCode 4, a powerful development environment for creating apps for both iOS and Mac OS X. XCode 4 is now officially available free of charge to registered Apple developers.
If you’re not a developer, you can purchase XCode 4 from Mac App Store at $4.99. Each Mac OS X ships with development tool for creating apps for Mac OS X. The tools include XCode and the frameworks, SDKs required for creating apps, and is on DVD 2 and is not installed by default. This is the reason why Apple is making XCode 4 available for general public via the Mac App Store.