Código PHP:
<?
$url = "http://www.webdeanuncios.com/formulario.php";
$handler = curl_init();
curl_setopt($handler, CURLOPT_URL, $url);
curl_setopt ($handler, CURLOPT_POST, 1);
curl_setopt ($handler, CURLOPT_POSTFIELDS, "titulo=valor1&texto=valor2&mail=tuemial");
$response = curl_exec ($handler);
curl_close($handler);
?>
Saludos