Ask HN: What's the best way to learn ObjectiveC for to code iPhone/iPad Apps?

I've been coding Ruby for a good 4 years now and would. HTML/CSS/Php for 8. I'd like to think I'm good at it. I want to build a simple iPhone App to start with then maybe something bigger.<p>There's about a million books on Amazon to buy about learning ObjectiveC, and sites like Treehouse for tutorials. I was wondering what the best place to start is?