Run a file seperately like a cron with wget using php?

$parts=parse_url('http://mysite.com/update.php'); //This is the file you want to run in the background

$fp = fsockopen($parts['host'],
isset($parts['port'])?$parts['port']:80,
$errno, $errstr, 30);

if (!$fp) {
} else {
    $out = "POST ".$parts['path']." HTTP/1.1\r\n";
    $out.= "Host: ".$parts['host']."\r\n";
    $out.= "Content-Type: application/x-www-form-urlencoded\r\n";
    $out.= "Content-Length: ".strlen($parts['query'])."\r\n";
    $out.= "Connection: Close\r\n\r\n";
    if (isset($parts['query'])) $out.= $parts['query'];

    fwrite($fp, $out);
    fclose($fp);
}