Is it possible to code this sequence of events once an iPhone app has been launched?
I've only seen app examples that load the MainWindow.xib without conditions.
If it is possible, which method in AppDelegate.m handles the logic? (applicationDidFinishLaunching? viewDidLoad?)
I don't think you want to load the MainWindow conditionally. Instead, load and show a viewController conditionally. This can be done in applicationDidFinishLaunching.