php mailer

<html>
<body>
<form method="post">
<input type="text" name="email"/>
<input type="submit" name="kirim"/>
</form>
<?php
    if (isset($_POST["kirim"])){
        $email = $_POST["email"];
    $filtered_email = filter_var($email, FILTER_VALIDATE_EMAIL); //Awal verifikasi email
    if ($filtered_email != false) {
    // $filtered_email is the valid email got out of $email
    $to = "$email"; //kepada
    $subject = "Selamat Datang";    //judul pesan
    $message = "Selamat anda telah berhasi mendaftar."; //isi pesan
    $from = "starkwek1.orgfree.com";        //Dari siapa

    $headers = 'MIME-Version: 1.0' . "\r\n";
    $headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n";
    $headers .= 'To: ' . "\r\n";
    $headers .= 'From: '. $from.' ' . "\r\n";
    $mail_sent = @mail($to,$subject,$message,$headers); //urutan pengiriman
    echo $mail_sent ? "" : "";
    } else {
    // nothing valid can be found in $email
    echo "Email tidak valid, Coba ulang lagi";
    }
    }

?>
</body>
</html>