Do you know Objective-C? Do you know any C? If the answer is no to either of these, then definitely start here. This class ramps up very well for a beginner and covers most of what you'd need to know to make a complete application from design to delivery.
Some basic programming / scripting knowledge is required.
A laptop with Snow Leapord and XCode
Download it here: https://developer.apple.com/xcode/index.php
About 3-4 hours