This is primarily for making iPhone-only versions of an existing site/application.
<meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1, minimum-scale=1, maximum-scale=1">
<!-- For iPhone: -->
<link media="only screen and (max-device-width: 480px)" href="small-device.css" type= "text/css" rel="stylesheet">
<!-- For everything else: -->
<link media="screen and (min-device-width: 481px)" href="not-small-device.css" type="text/css" rel="stylesheet">
html { -webkit-text-size-adjust: none; }
If you want your site/application to run in full screen mode (and separated from the normal mobile Safari) when running from a home screen shortcut, add this meta tag:
<meta name="apple-mobile-web-app-capable" content="yes">
Don't forget to add a nice icon for people who bookmark your site on their home screens.
<link rel="apple-touch-icon" href="/img/touch_icon.png">
user-scalable=no
... shame on you, really!