Now here’s a tip for doing native-appearing Web applications for the iPhone that an AppleInsider reader found: simply add
<meta name="apple-mobile-web-app-capable" content="yes" />
to your Web page code. Then, once the user adds it to their Home Screen, it’ll launch in full screen without the Safari chrome visible. Demo can be found here.
That’s a pretty nifty feature for any WebKit-writable project you may have in mind, indeed!
h/t: AppleInsider!

it’s not really a secret considering its stated in the iphone web development documentation. Another neat tip is the meta tag to change the status bar colour from grey, to black, to transparent black
<meta name=”apple-mobile-web-app-status-bar-style” content=”black” />