I'm frequently asked about resources and tutorials for learning to develop applications for the iPhone. There are a lot of books and tutorials out there. I've put together this list of some of the ones I use and recommend. Enjoy.

First up, definitely check out these four iPhone specific references from Apple's iPhone Developer Center

• iPhone Application Programming Guide
• iPhone Development Guide
• iPhone Human Interface Guidelines
• Your First iPhone Application

You'll spend a lot of time in Xcode and Interface Builder (IB) so also check these out.

• A Tour of Xcode
• Interface Builder User Guide

For more of the basics of Objective-C

• The Objective-C Programming Language
• Object-Oriented Programming with Objective-C
• Learning Objective-C: A Primer

And if you're also interested in desktop Cocoa programming these should get you started.

• Become an Xcoder
• Cocoa Fundamentals Guide
• Cocoa Application Tutorial

If you are looking for a third party book, these have been helpful and there are many others

• Beginning iPhone 3 Development: Exploring the iPhone SDK
• Programming in Objective-C 2.0
• Cocoa(R) Programming for Mac(R) OS X

iTunes U and Stanford have a great college class presented in a podcast

• iPhone Application Programming

And if you want more personal training and information check out

• My 8-hour App iPhone development class

Let me know if there are others that I should add. Thanks.