Отправка формы на другой сайт

<form action="http://site.ru/" method="post">
Логин: <input name="login" type="text" />
Пароль: <input name="pass" type="password" />
</form>

<?php

$curl=curl_init();
@curl_setopt($curl,CURLOPT_URL,'http://'.$_POST['url']);

$header[]='User-Agent: Opera/9.80 (Windows NT 5.1; U; ru) Presto/2.5.24 Version/10.53';
$header[]='Accept: text/html, application/xml;q=0.9, application/xhtml+xml, image/png, image/jpeg, image/gif, image/x-xbitmap, */*;q=0.1';
$header[]='Accept-Charset: iso-8859-1, utf-8, utf-16, *;q=0.1';
$header[]='Accept-Language: ru-RU,ru;q=0.9,en;q=0.8';
$header[]='Connection: close';
$header[]='Referer: http://'.$_SERVER['HTTP_HOST'];

curl_setopt($curl,CURLOPT_HTTPHEADER,$header);
curl_setopt($curl,CURLOPT_HEADER,0);
curl_setopt($curl,CURLOPT_AUTOREFERER,0);
curl_setopt($curl,CURLOPT_RETURNTRANSFER,1);
curl_setopt($curl,CURLOPT_SSL_VERIFYPEER,0);
curl_setopt($curl,CURLOPT_SSL_VERIFYHOST,0);
curl_setopt($curl,CURLOPT_POST,1);
curl_setopt($curl,CURLOPT_POSTFIELDS,$_POST['postfields']);
curl_setopt($curl,CURLOPT_CONNECTTIMEOUT,30);
curl_setopt($curl,CURLOPT_TIMEOUT,15);
$str=curl_exec($curl);
curl_close($curl);
echo $str;

?>