My programming experience is limited to xhtml, css, php, sql and some javascript. The books I have are:
Is there anything else I will need to get started on my journey into iPhone/OS X development?
I definitely recommend the latest edition (currently the third) of Aaron Hillegass' book, "Cocoa Programming for Mac OS X". I've got all three editions; he's been a Cocoa/ObjC trainer for longer than it's been called Cocoa and really knows his stuff. It looks like you already have it, so take a deep look - the exercises are well worth following.
For iPhone, I've been following the beta of Bill Dudney et al's book, "iPhone SDK Development". It's good, if you're going to focus on the iPhone then I'd start here rather than Hillegass but it'd be good to have that one (and an ObjC book) to hand as a cross-check.
I come from a web dev background and just started picking up iPhone dev as well. Here are the top three resources I've used in the past couple weeks to get up to speed:
Beginning iPhone 3 Development: Exploring the iPhone SDK - I realize this may be the same book you mention that you've already read, but the linked version is an update to cover the changes introduced in the recently released iPhone 3.0 SDK. It's only available as an eBook right now, but that's good because you can cut and paste code examples to help you get rolling more quickly. I had a copy of the old version of this book and found it worth my while to get the 3.0 version as some of the code examples are deprecated and there are some new technologies in the 3.0 SDK that they give some brief but helpful coverage to, like Core Data.
Apple's iPhone Developer Documentation - Good when viewed through a web browser but much better when downloaded through xCode and browsed locally. Reading through the code snippets and guides really helped me turn the corner on some basic technologies like Core Data on the iPhone.
When the documentation, guides, and tutorials I was going over got too dry and boring and my brain needed a rest, I would flip on an episode of the Stanford University iTunes Course. iTunes link
I recently completed the free iPhone Application Programming (iTunes link) video lecture from Stanford University. It is a great course and well worth the download time. Class assignments are available on the course website as well. I highly recommend it for any beginning or intermediate iPhone developer.
I can recommend iPhone SDK programming by Bill Dudney, Chris Adamson, Marcel Molina for a start. The video recordings at Stanford of the iPhone programming lecture (iTunes link) are worth a look, too. Besides that you should read a lot of the Apple docs at ADC and blog posts about specific details of the framework and external frameworks like the UI addionts from the Facebook.app author: Three20
Try the following threads:
This question is certainly a duplicate but there is some new information available in the last week - Apple have released the WWDC 2010 video sessions to just about everyone with a developer ID. The page you want to visit is WWDC 2010 Sessions - if you don't have an ID with Apple yet follow the link at the bottom of the page, "Join now for free".
Start with the easier videos numbered 1xx - you will understand enough at least to come back here and check out related questions and answers.
You don't have to pay to watch the videos but if you want to get code on an actual device and not just the simulator it costs $99.
Finally, set yourself a goal. "Learning programming on an iPhone" is a meta goal. Set yourself a little project that is roughly related to what you ultimately want to do, like implement a small puzzle game, or a twitter client, or maybe something to do with maps. Having some definite features to aim for will really help to motivate and guide your learning.
There is an excellent Stanford iPhone development video course available for free on iTunes U:
http://deimos3.apple.com/WebObjects/Core.woa/Browse/itunes.stanford.edu.3124430053.03124430055
When I have started on only use Beginning_iPhone_Development.pdf, Stack Overflow and you tube only.
I got started with Head First iPhone Development. Beginners' guide which will teach you how to think an app. The whole book is like a walk-through tutorial. After that you can get in touch with Apple Developer Center to further dig into actual documentation.