gistfile1.txt

AppDelegate.m

- (IBAction) switchViews
{
    if (self.window.rootViewController == self.viewController) {
        self.window.rootViewController = self.settingsNavigationViewController;
    } else {
        self.window.rootViewController = self.viewController;
    }
}

AppDelegate.h

#import <UIKit/UIKit.h>

@class FlicktasticViewController;

@class SettingsViewController;

@interface FlicktasticAppDelegate : NSObject <UIApplicationDelegate> {

}

@property (nonatomic, retain) IBOutlet UIWindow *window;

@property (nonatomic, retain) IBOutlet FlicktasticViewController *viewController;

@property (nonatomic, retain) IBOutlet UINavigationController *settingsNavigationViewController;

- (IBAction) switchViews;

@end

Both view controllers are created in MainWindow.xib