Reddit mentions of Tapworthy: Designing Great iPhone Apps

I can't think of any 'modern' books, I bought one a long time ago called 'tapworthy' but that was like 6 or 7 years ago
https://www.amazon.com/Tapworthy-Designing-Great-iPhone-Apps/dp/1449381650

I read it a long time ago, but honestly, nothing really stand out off hand as to how good it was. I was new to iPhones back then and was reading anything :D

There's sites, but I can't remember them off the top of the head. Most talk about colors usage and screen layout. It's kinda like looking at all the new "latest-n-greatest" web/mobile stuff.

tapworthy is a good one, also apple's Human Interface Guidelines

Awesome, I'm glad. I can recommend other books as well, but some, I'm still in the process of reading. I highly recommend TapWorthy because the look and feel of the app is sometimes worth more than the function of the app.

http://www.amazon.com/Tapworthy-Designing-Great-iPhone-Apps/dp/1449381650/ref=sr_1_1?ie=UTF8&qid=1342486467&sr=8-1&keywords=tapworthy

Best practices in mobile UI design are still evolving. The most complete source today is a book—Tapworthy by Josh Clark.

If you're just looking for design inspiration, there are some decent mobile design galleries out there, like Tappgala.

Smashing Magazine is just beginning to pick up the pace on mobile UI design, so keep an eye on that. The only mobile design blog I pay attention to is Luke Wroblewski's.

For learning Objective-C, I'd recommend this book by the guys at the Big Nerd Ranch. I've had a look through it recently and it teaches you quite a bit of programming with C, then how to transfer that knowledge to Objective-C, using the Foundation + AppKit & UIKit frameworks. (Speaking of UIKit, have a look at the UIKit Framework Reference to see all the cool things you can do with it.)

With that said, knowing how to write apps != knowing how to write great apps. For that, you'd want to start by taking a look at the Human Interface Guidelines, which will teach you how to go about designing various UI features and how to make your software fit in on the platform you're developing it for, be it the Mac or iOS.

For learning a bit about designing the apps themselves, Tapworthy isn't a bad book to start with. I often hear people say that once they know how to code, they'll be able to make amazing apps for the iPhone, but if you ask me, learning how to program is the easy part. Making software work efficiently and beautifully is often a lot trickier than it sounds.

Other than all of that, I agree with xPaQx; Stack Overflow is an amazing resource with incredibly smart people willing to help out to the best of their ability, and has probably taught me more than any book has so far. Also, feel free to PM me with any questions you have – I'd love to help.