For anyone who actually wants to build an app -- This guide is very long winded. For iOS, the easiest way is to download xCode and try to build it.

I would suggest Aaron Hillegass' Big Nerd Ranch Guides for ObjC and iOS programming. I read those books over a few days to get started and felt as though they provided a great foundation for all ObjC things to come. Stack Overflow fills in the blanks.

You don't have to take my advice, but it's been 8 months since I started "building my killer app", it's been out in the app store for almost 5 months, and since then we've been featured by Apple, and have over 50K users. Just plan to start what you've finished and you'll force yourself into having a killer app.