Software development for Mac OS X and iOS is a lucrative market right now and to get into it you need to learn languages like Cocoa and Objective-C. Xcode is a suite of tools that supports these languages and allows you to develop software for the Apple platforms. Here is a list of the top ten resources to learn Xcode.
No 10. Objective-C Programming: The Big Nerd Ranch Guide
This book covers C, Objective-Ca, and other common programming idioms. It covers Programming basics like variables, loops, functions, objects, classes, methods, messages, pointers, addresses, and memory management.
More importantly, it is compatible with Xcode 4.2, iOS 5, and Mac OS X 10.7 and takes you thorugh step by step on how to code in Xcode.
No 9. iOS Programming: The Big Nerd Ranch Guide (2nd Edition)
The authors take the reader through all the Apple tools and technologies (including Xcode 4) needed to build successful iPhone/iPad/iPod touch apps.
No 8. Pro iOS 5 Tools: Xcode Instruments and Build Tools
This book teaches you all the tools available to all iOS developers: Xcode, Instruments, network diagnostic tools and version control. Get this book if you are looking to learn iOS programming in Xcode.