DRAFT
Someone asked me recently: how long does it take a seasoned .NET/C# developer to become a useful iOS developer? Good question. Gets asked a lot, actually.
So here's the deal with iOS. You're writing Objective-C. That's the language for both iOS and Mac OS X. Basically Smalltalk-style messaging bolted onto C. Anything you can do in C, you can do in Objective-C. Weird syntax at first. You get used to it.