Lots of books/tutorials always use Interface Builder and XIB which I don't like it. There's also rarely any information about doing things using C or C++.
Another area still not very clear is the memory management part.
Also read tutorials about using multiple images to create basic animation. But then how do you control user touching/tapping on the image/sprite thing? Lots of challenges ahead!
Saw some guys started a thread on iPhone development forum using simple tic tac toe game as a starting point. This is quite good idea. Might do something similar as a start.