i use this code in our main template to switch the theme.
<?php
$iphone = strpos($_SERVER['HTTP_USER_AGENT'],"iPhone");
$android = strpos($_SERVER['HTTP_USER_AGENT'],"Android");
$palmpre = strpos($_SERVER['HTTP_USER_AGENT'],"webOS");
$berry = strpos($_SERVER['HTTP_USER_AGENT'],"BlackBerry");
$ipod = strpos($_SERVER['HTTP_USER_AGENT'],"iPod");
$ipad = strpos($_SERVER['HTTP_USER_AGENT'],"iPad");
if ($iphone || $android || $palmpre || $ipod || $ipad || $berry == true)
{
echo "<script>window.location='http://idmworks.com/mobile-home'</script>";
}
?>
that url has it's own menu that only points to mobile themed pages