So, if you want an iPhone-enabled version of your Drupal website, all you have to do is install the http://drupal.org/project/iui   iUI Drupal Theme, and then switch to the iUI theme when the user visits your mobile-enabled website. You could do that by either a small hack in settings.php, or one of the many modules out there that changes the theme based on the user agent or the domain. 

Features (so far)

• Integrates perfectly with the iPhone (vertically or horizontally)
• Back and forward button page slide
• Throbber animation when loading new pages
• Browse through primary and secondary links
• Display nodes and pages in the Details menu item