I've been programming for the iPhone for quite some time now. I have read books like Beginning iPhone 4 Development by Jeff LaMarche and Programming in Objective C by Stephen Kochan. Right now I am pretty comfortable with view controllers, table views, gestures, GCD, Core Data etc.
I am now seeking to build a career in iOS (instead of a hobby as it has so far been). How can I take my knowledge to the next level so that I can be hired as a profesional iOS developer. What are the other technologies I must be familiar with in order to be comfortable building enterprise level applications for different industries like banking, telecommunications etc? Are there any good books that talk from the perspective of enterprise architecture for mobile applications ?