This book has many strong sides but being an introductory text for someone looking to learn to write their first iPhone app is not one of them. Apart from that, I believe the book is much longer than it could have been.
Programming iOS is a great reference complete with an overview of Objective C, IDE and Cocoa, among other things, but it's hard to see how to glue everything together without an understanding how to build simple iPhone apps. There is a Hello, World! example somewhere around pages 100-150 but then this example isn't developed further, so most other concepts are illustrated with pieces of code that the reader is supposed to try in their projects on their own.
This book makes a great reference, though. It's well organised (take a look at the TOC) and somewhat pedantic in explaining everything systematically. If you can build basic apps, this book is likely to be useful. However, as the first introductory text this book is not the best choice.
I also wish this book were shorter. Dozens of pages are dedicated to describing menu items, the process of submission to the Apple store, explaining every piece of information that you are supposed to have etc. Don't forget it's 800 pages; it's not a paperback you want to carry around in your messenger bag with your laptop.
So, I'm giving it 3 stars because it could definitely be more concise and its description should clearly state that it's more of a reference than an introductory text.