iOS 4/XCode 4 explained,
This review is from: Programming iOS 4: Fundamentals of iPhone, iPad, and iPod touch Development (Definitive Guide) (Paperback)
Programming iOS 4 is one of the publications available on market that are devoted to iOS related programming. And I was quite impressed when I was reading it. First of all, it is based not only on iOS 4 but on XCode 4 as well. This is huge advantage because you don't have to think about transition between XCode 3 and XCode 4 while reading the book. Not only book is based on the XCode, but Matt provides you with an introduction to the tool. This way you can get familiar with it fairly easy. You will find information regarding how to access documentation, how to deal with code snippets, how to deal with code completion (BTW - if you are moving from any other IDE I suggest replacing Esc with Ctrl+space for code completion being invoked), static analysis of the code. It's a pity that this is another book where Instruments are not explained in greater details.
iOS development is based on Objective-C, which means that you have to get familiar with it when you move on from Java/C# world. Matt provides you with an introduction to the language. This section contain basic information related to C and Objective-C. Be warned here. I'd definitely suggest to buy some solid C guide - like a classic "C Language" by K&R. The same situation relates to Objective-C, go and buy something that is entirely devoted to language itself - Programming in Objective-C by G. Kochan would be good idea. However, this is not mandatory. If you need just a brief overview of the language, Matt provides all you need here. However, there are small issues in C introduction. Matt refers to "nil" which is not C standard - it is introduced by Objective-C. The same refers to NSString object. As far as I recall, you can't use them in pure C.
After making you familiar with development environment Matt goes over features of iOS API and presents various aspects of iPhone programming. You won't get here complete solutions, instead he focuses on what's most important in each case. This way you can briefly go over the topics and focus on what's most important for you. At some point it might be irritating, because it looks like not much more than API description from the documentation, but in most cases it's something more than that.
In general, I find it quite useful. I have found few topics that I was not aware of after moving to XCode 4. I think the book is worth reading.