iOS 6 UITabBarController supported orientation with current UINavigation controller

Subclass your UITabBarController overriding these methods:

-(BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    // You do not need this method if you are not supporting earlier iOS Versions
    return [self.selectedViewController shouldAutorotateToInterfaceOrientation:interfaceOrientation];
}

-(NSUInteger)supportedInterfaceOrientations
{
    return [self.selectedViewController supportedInterfaceOrientations];
}

-(BOOL)shouldAutorotate
{
    return YES;
}

Subclass your UINavigationController overriding these methods:

-(NSUInteger)supportedInterfaceOrientations
{
    return [self.topViewController supportedInterfaceOrientations];
}

-(BOOL)shouldAutorotate
{
    return YES;
}

Then implement these methods in your viewControllers that you do not want to rotate:

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

-(BOOL)shouldAutorotate
{
    return NO;
}

-(NSUInteger)supportedInterfaceOrientations
{
    return UIInterfaceOrientationMaskPortrait;
}

And for viewControllers that you do want to rotate:

    - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
    {
        return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
    }

    -(NSUInteger)supportedInterfaceOrientations
    {
        return UIInterfaceOrientationMaskAllButUpsideDown;
    }

    -(BOOL)shouldAutorotate
    {
        return YES;
    }

Your tabbarController should be added as the RootviewController of the app window. If you plan to support the default orientations, all but upsidedown is default for iPhone, then you do not need to do anything else. If you want to support upside-down or if you do not want to support another of the orientations, then you need to set the appropriate values in app delegate and/or info.plist.