I have a UIScrollView that shows vertical data, but where the horizontal component is no wider than the screen of the iPhone. The problem is that the user is still able to drag
Something to keep in mind: You know there's nothing extra to see horizontally, but will your users know that? You may want a little horizontal bounce, even if there's no extra content to show horizontally. This let's the user know that their attempts to scroll horizontally are not being ignored, there's just nothing there for them to see. But, yeah, often you really don't want the bounce.