iPhone user agent detection

[4789787]

First off iv developed a web based iphone game im putting on the appstore for money so of course it wouldnt be fair if users played on the computer free without paying.

Ok what i need to do is to have a page that detects the iPhone browser and loads the page. lol thats the easy part the hard part is if the browser is ANYTHING other than the iPhone browser the page will redirect to another page. I know this is possible because iv seen it done i just cant figure out how. I found this code but it only blocks certain browsers and the player of my game could just change their user agent and play for free

CODE:

<script language="JavaScript"
type="text/JavaScript">
if(navigator.appName == "Microsoft Internet Explorer")
{
window.location = "ragespace.html"
}
if(navigator.appName == "Netscape")
{
window.location = "ragespace.html"
}
</script>

[aj_nsc]

http://iphone.wikidot.com/detection

google is such a simple, yet powerful, tool to use.

EDIT: I should probably take the time to clarify that useragent detection is not the ideal since it can be changed by the user. The below link appears to be a very good alternative:
http://webkit.org/blog/119/webkit-de...nd-ipod-touch/