[m r wilson]

I know a lot of this stuff is in the great wiki here, but here's Apple's official word on developing web apps specifically for the iPhone:

http://developer.apple.com/iphone/designingcontent.html

[poetic_folly]

Nice. Here is some stuff I am glad to see:

"*

A link to a phone number looks like this:

1-408-555-5555

If you don’t wrap phone numbers in a link, Safari automatically converts any number that takes the form of a phone number to a telephone link. If your page contains a series of numbers that could be interpreted as a phone number, but isn’t, you need to break up the numbers using span elements, for example.
*

Mail links open a built-in mail compose sheet.

John Frank

*

Google maps links open a built-in Google client rather than making a connection through the public website.

This link opens to a point on a map (Cupertino, California):

Cupertino

This link provides directions between two points, San Francisco and Cupertino:

Directions

Remember that users use a finger to choose a link. If you put links too close together on a page, your users may not be able to select the one they want."