Ok, I written about a dozen iPhone apps, several are already in the App store. But I haven't developed any new Mac apps from scratch since the days of System 7 and 68k CPUs. What do I need to learn to transition from developing OS X apps for the iPhone to writing contemporary apps for desktop Macs and MacBooks? I suppose I need to learn how to handle the menu bar and more than one window in Cocoa. Anything else necessary or critical? Are there any tutorials targeted for programmers who already know basic Objective C for UIKit, rather than the other way? .