Check out this stanford course, it is an excellent resource for learning everything you need to know:
You have to ask yourself whether you want to learn to develop iPhone apps, or whether you just want to copy examples. Tutorials are great, but if all you do is tutorials and you never pick up a book then you'll never get the bigger picture. And the big picture is critical for an API like Cocoa. There are a lot of basic concepts (like delegates) that may be unfamiliar and confusing until you understand the underlying design patterns.
Apple's developer guides are quite good -- and maybe you can just tell youself they're not really books because they're online? :) I'd <strong>strongly</strong> recommend reading through them along with tutorials (or videos).
<li>iOS Technology Overview</li>
<li>iOS Application Programming Guide</li>
I agree with both Skue and Burt. Additionally, if you are a registered ios developer, you will have access to developer videos, which I found very useful personally, specially when I didn't want to read text books :) ios development is a vast arena of programming, so I think the best way to start learning is by start coding. Some things for you to start up with: 1. iPhone tutorials 2. Sample apps
Plus, for learning objective-c , I would suggest Apple's doc on Programming to Objective-C and finally, a text book - Programming in Objective-C by Stephen Kochan.
As a comment I'd like to recommend you to skim through thenewboston objective-c series and thenewboston iphone dev series which actually got me started in the language and iPhone dev about 6 months ago.