This is the software publisher's description.

Xcode is the complete toolset for building Mac OS X and iOS applications — and with Xcode 4, the tools have been redesigned to be faster, easier to use, and more helpful than ever before. The Xcode IDE understands your project’s every detail, identifies mistakes in both syntax and logic, and will even fix your code for you. Quite simply, Xcode 4 will help you write better code.

In Xcode 4, Interface Builder has been completely integrated within the Xcode IDE — there is no separate application.

Selecting an interface file (.nib/.xib) in your project will open the IB editor within Xcode. Opening the right-hand Utility area will show the full complement of interface inspectors, as well as the library of controls and UI objects. Drag a control from the library, and drop onto the canvas, to layout your Mac OS X or iOS application.

The best part: you can drag connections directly from the UI design to the source code. Xcode 4’s new split editor layout makes it easy to wire up your actions and outlets simply by dragging a connection to existing code — one gesture and you’re done. Don’t yet have the code ready to connect? Xcode will create a new outlet or action for you, just drag to an empty space in your source file and Xcode will generate the code.

Xcode 4 has a brand new user interface, built upon proven technologies that Apple itself uses to build Mac OS X and iOS, and that have produced over a quarter million Mac OS X and iOS apps.

Verdict

Powerful free tool that will enable you to create your own OS X or iOS app. Programming experience required, clearly.