A couple weeks ago I attended the Web 2.0 Expo in San Francisco. One of the sessions was on iPhone Tips and Tricks delivered by Alex Shah from Team SOA. The basic idea is that you can avoid the development time and the Apple App Store approval process for your iPhone application by creating a browser-based application using the open source Webkit software.
There is enough capability (using some tricks to get to them) to create a complete application that looks like it is a native iPhone application but is actually running in the Safari browser. Better yet, your browser-based app can run on other mobile phones and of course ordinary computers where a browser can be used.
This is an interesting approach to writing one application that can run on multiple mobile platforms. Now Google has “validated” this approach by using it for the lasted update to the Gmail service for users of the iPhone and Android phones. It’s written up in an article about how Gmail Sidesteps the App Store.