A UIViewController subclass that allows one to easily set the allowed orientations and content orientation.

OrientatedViewController.h

//
//  OrientatedViewController.h
//
//  Created by Shilo White on 10/30/11.
//  Copyright (c) 2011 Shilocity Productions. All rights reserved.
//

#import <UIKit/UIKit.h>

typedef enum {
    AllowedOrientationPortrait              = 1 << 1,
    AllowedOrientationPortraitUpsideDown    = 1 << 2,
    AllowedOrientationLandscapeRight        = 1 << 3,
    AllowedOrientationLandscapeLeft         = 1 << 4,
    AllowedOrientationAll                   = 30
} AllowedOrientation;

@interface OrientatedViewController : UIViewController {
    UIInterfaceOrientation _contentOrientation;
    AllowedOrientation _allowedOrientation;
}

@property (nonatomic, assign, readwrite) AllowedOrientation allowedOrientation;
@property (nonatomic, assign, readwrite) UIInterfaceOrientation contentOrientation;

@end

OrientatedViewController.m

//
//  OrientatedViewController.m
//
//  Created by Shilo White on 10/30/11.
//  Copyright (c) 2011 Shilocity Productions. All rights reserved.
//

#import "OrientatedViewController.h"

@protocol OrientatedViewControllerSubclass <NSObject>
- (void)orientateContentToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation duration:(NSTimeInterval)duration;
@end

@interface OrientatedViewController ()
- (BOOL)shouldAllowInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation;
@end

@implementation OrientatedViewController

@synthesize allowedOrientation = _allowedOrientation;
@synthesize contentOrientation = _contentOrientation;

- (id)init {
    if ((self = [super init])) {
        _allowedOrientation = AllowedOrientationAll;
        _contentOrientation = self.interfaceOrientation;
    }
    return self;
}

- (void)viewDidLoad {
    [super viewDidLoad];
    _contentOrientation = self.interfaceOrientation;
}

- (BOOL)shouldAllowInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    return (((1<<interfaceOrientation) & _allowedOrientation) > 0);
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    return [self shouldAllowInterfaceOrientation:interfaceOrientation];
}

- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {
    if (_contentOrientation != toInterfaceOrientation) {
        _contentOrientation = toInterfaceOrientation;
        if ([self respondsToSelector:@selector(orientateContentToInterfaceOrientation:duration:)])
            [(id<OrientatedViewControllerSubclass>)self orientateContentToInterfaceOrientation:toInterfaceOrientation duration:duration];
    }
}

- (void)dealloc {
    [super dealloc];
}
@end