Tutorials is a project mainly written in Objective-C, it's free.
iPhone/iPad Development Tutorials
http://developer.apple.com/library/ios/navigation/
Apple has some of the most comprehensive developer documentation you'll ever come across, with samples of the majority of scenarios you may encounter, use it.
A number of tutorials for developing on the iPhone/iPad.
Here is the list of tutorials, view each README first:
I have also got some other tutorials I've made: