There are a lot of great lectures on learning iOS development on the iTunesU network free for download. But it’s slow going and I’d rather code than watch lectures about it.
This guy has a bunch of links and this is where I’ve started a few days ago with iOS.
“Can you recommend a good book for getting started with Objective-C?”
I get this question a lot, but there’s no need to spend any money or even to spend time digesting an entire book. I always point people to the Apple docs — the documentation is very modular and (mostly) very reliable.