Apple posted Web Development guidelines for the iPhone.
Developers can create Web 2.0 applications that look and behave just like the applications built into iPhone, and provide seamless integration with iPhone applications and services including making a phone call, sending an email, and displaying a location in Google Maps. Third-party applications created using web standards can extend iPhone's capabilities without compromising its reliability or security.
The Guidelines are organized into:
Understanding User-iPhone Interaction
Use Standards and Tried-and True Design Practices
Integrate with Phone, Mail and MAps
Optimize for Page Readability
Ensure a Great Audio and Video Experience
Know What Safari Supports on iPhone
Connect With Web Developers
A few web applications have already been released for the iPhone, but development has been very much by trial and error for these early iPhone applications.
Visit our iPhone App and Development forum for iPhone application discussion and releases.