Make sure this is in your BODY command:

onLoad=choose()



<SCRIPT LANGUAGE="JavaScript">
<!--
// Here's a script so you can make
// really cool pages for PC users
// and crappy, boring ones for Mac
// users.  Just replace the html file 
// names with the ones you have made.
// Enjoy the script!
// ron_gallagher@yahoo.com
// -->

function choose() {
    AppVer = parseInt(navigator.appVersion);
	if(navigator.appVersion.indexOf("Mac") != -1){
        location.href = "macindex.html";
    } else {
        location.href = "pcindex.html";
    }
}
</SCRIPT>