A while ago, I stumbled across the Stanford iPhone courses on iTunesU. The courses are videos of the actual iPhone development course at Stanford University. I used these a few months ago to get familiar with the XCode IDE and the iPhone SDK.
Now that I actually landed a small gig as an iPhone developer, I have been thrown into the belly of the beast. Because I'm in such a fast-paced environment, I'm learning WHAT to do to get things working, but not so much WHY I'm doing it this way. I'd rather not be solely a creature of habit, and would like to understand the inner-workings of the code that I'm....coding.
With that being said, I decided to take some time and revisit the Stanford iPhone course. I believe this will be time well-spent; an investment in my future as a Cocoa/ Objective-C developer. After finishing the first episode, I feel enlightened on a couple of nagging issues I had before. I'm sure this trend will continue as I progress through the course.
I actually found another iPhone course at RWTH Aachen (a German school). Maybe I'll check this out another time.