iPhone and HTML5 Applications
The iPhone supports offline HTML5 based applications. This is interesting, because it enables what Apple seems to be trying to prevent: applications that you can write once and run anywhere. And download and install, for free. With no review process.
Check this out: http://sixrevisions.com/web-development/html5-iphone-app/
Now, I don't know what the logistics would be of trying to sell one of these, but I expect it's possible to write a wrapper Objective C app that bundled the HTML5 app and launched it in the WebKit on the phone.
But what happens if this takes off?
I don't trust that Apple wouldn't shut it down if it interfered with their App Store goals.