if you want to test different landing pages try this neat little php code (found it somewhere here on the forum and saved it, cant remember who wrote it though)
<?
$lps = array(
'http://127.0.0.1/landingpage1.php',
'http://127.0.0.1/landingpage2.php',
'http://127.0.0.1/landingpage3.php',
'http://127.0.0.1/landingpage4.php',
);
header('Location: ' . $lps[array_rand($lps)]);
?>