<?PHP
if(!empty($_SERVER['HTTP_REFERER']))
{
// Поисковой робот
$search = 'none';
if(strpos($reff,"yandex"))
{
$search = 'Yandex';
}

if(strpos($reff,"rambler"))
{
$search = 'rambler';
}

$text = "";

if($search == "yandex")
{
eregi("text=([^&]*)", $reff."&", $query);

if(strpos($reff,"yandpage")!=null)
{
$text = convert_cyr_string(urldecode($query[1]),"k","w");
}

else

{
$text = $query[1];
}
}

if($search == "rambler")
{
eregi("words=([^&]*)", $reff."&", $query);
$text = $query[1];
}

if(!empty($text))
{
include("mysql.php");
mysql_query("INSERT INTO search (text) values ('$text')");
}
}
?>

взято с Форум программистов www.forum.webering.ru и WEB DISIGN WEBERING.RU