Others have requested improvements to the scrolling methods of the iphone so I'll add my suggestion. It's mainly for scrolling the Bible. As far as I can tell, a tap or swipe down tells the app to bring up the verse finder on the top of the screen. We could keep that but also add the following:
Moving your finger up or down on the far right edge of the screen brings up a dialogue box that allows you to "scroll" up or down with your finger to a specific verse in the current chapter.
The same thing could be applied to the left hand edge but it could allow you to scroll to a specific chapter in the current book.