I have noticed something interesting: When visiting certain Apple websites (MobileMe sites in particular) on the iPhone, the URL is modified, with /iPhone/ being interjected. Thus the iPhone is being recognized as the originator, and the site is tailored accordingly. The problem here is that you don't necessarily get to the site you really want.
For example, if you want to go to me.com, you don't get to log in there, but rather you get a page advertising MobileMe. Obviously Apple is trying to tell you that you have direct access to MobileMe through other means on the iPhone. This doesn't help if the MobileMe feature you wish to avail yourself of doesn't work on the iPhone, such as sending from MobileMe aliases or viewing subscribed calendars.
Now I've noticed another instance of where this acts to your disadvantage on the iPhone. If you create a private webgallery (i.e., have it not listed in your main web gallery index), e-mail the notification of the direct URL, and then click on the direct URL on the iPhone, you don't get the page you want. Instead, the iPhone takes you to the top level of your web gallery where, of course, that private gallery is not linked.
What does work is, after you have arrived at your top level web gallery page, scroll to the top and edit the URL on this page to append the gallery ID number (this gets deleted when the /iPhone/ bit gets inserted), but this is a pain in the neck, and not at all Apple-like.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20080804065204249