<?
$ch =  curl_init ();
curl_setopt ($ch, CURLOPT_URL,"sex.com/p/register.cgi");
curl_setopt ($ch, CURLOPT_POST, 1);
curl_setopt ($ch, CURLOPT_REFERER, "sex.com/go/g99999");
curl_setopt ($ch, CURLOPT_POSTFIELDS, "a=3&b=5"); // смотрим параметры формы на sex.com/go/g99999
    //--- Start buffering
ob_start ();
curl_exec ($ch);
    //--- End buffering and clean output
ob_end_clean ();

curl_close ($ch);
?>