I just read the Apple Safari Web Clips guidelines and it clearly states the .png format.
I am pretty sure that I have everything in the right format and in the right place,
for example:
www.johndkretschmer.com/apple-touch-icon.png
But the Web Clip image (favicon) does not work on my iPhone.
Could this have something to do with the domain name being different from the iWeb address?
The Web Clip icon is not the same as a Favicon you see in the addressfield of a browser.
You can use the same Web Clip icon as a favicon. Duplicate it and rename it favicon.ico.
No need to add code to iWeb either. Any modern browser will find it in the root of the webserver.
It does not work when you use web.me.com/username (or any service where the user directory is not root), as the Web/Sites folder on iDisk is
not root in that case. You have to add the code to the <head> of the page :
<link rel="shortcut icon" href="favicon.ico" />
Why your Web Clip does not work on a iPhone is beyond me. Perhaps clearing the cache of Mobile Safari will help.
The PNG is not required to be at the root. Dashcode specifically reroutes users from the root to /Mobile if it finds you are on an iPhone, so Apple were never expecting these files to be found at the root of the site.
What does dictate the icon however is this tag: <link rel="apple-touch-icon" href="Images/WebClipIcon.png"> you can see the full path being used.
Chances are, your PNG is actually at www.rootfolder.com/Mobile/apple-touch-icon.png.
I also had to update the HTML that Dashcode produced to refer to the image correctly.
The original tag above needed to become: <link rel="apple-touch-icon" href="/Mobile/Images/WebClipIcon.png">
The first version should actually have worked as a relative link since it doesn't start with a slash, but providing an absolute link (led with a slash) was much easier.
By the way, the Apple dev tools (including Dashcode) are free (with a registration no doubt - no need for the paid one though) and quite frankly for building sites, iWeb is a total fail whereas Dashcode is fantastic.