iOSでポップアップビューを実装する(with Storyboard) ref: http://qiita.com/g-1/items/970d9101bdd14cbceffd

PopupViewController.m

- (void)viewDidLoad
{
  [super viewDidLoad];
  // Do any additional setup after loading the view from its nib.
  self.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
}

ViewController.m

- (void)viewDidLoad
{
  [super viewDidLoad];

  self.modalPresentationStyle = UIModalPresentationCurrentContext;

}