gistfile1.html

<div id="iphone-wrapper">
  <div id="iphone-wrapper-inner">
    <!-- put everything except the nav in here and give this a fixed height which is the 
    height of #iphone-wrapper minus the height of #nav. so this becomes our new scrolling 
    content area -->
  </div>

  <div id="nav">
    <!-- keep this as position absolute because #iphone-wrapper won't scroll (we let 
    #iphone-inner-wrapper do that instead) so we don't have to worry about it moving up. -->
  </div>
</div>