Aşağıdaki yazdığım toplu mail yollayıcıyı kullanabilirsiniz. Dosyayı utf8 destekli bir text editör ile utf8 encoding formatında kaydediniz.

Kod:

@header('Content-Type: text/html; charset=UTF-8'); 
if (!@set_time_limit(0))
{
    @ini_set("max_execution_time", 0);
}
error_reporting(1);
ob_implicit_flush (1);

###########################################################
###########################################################

$mail_dosyamiz = "maillist.txt";
$gonderen_mail = "hede@hodo.com";
$mail_charset  = "UTF-8";

###########################################################
###########################################################

// başlık
$konu = 'Konu başlığı buraya';

// mesaj
$mesaj = 'Mesaj içeriği buraya (html kullanabilirsiniz)';

function UTF8_mail($from, $to, $subject, $message)
{
    $from2 = explode("<", $from);
    
    if (isset($from2[0])) 
    {
        $headers = "From: =?UTF-8?B?" . base64_encode($from2[0]) . "?= <" . $from2[1] . "\r\n";
    } 
    else 
    {
        $headers = "From: " . $from[1]."\r\n";
    }
    //$subject  = "MIME-Version: 1.0" . "\r\n";
    $subject  = "=?UTF-8?B?" . base64_encode($subject) . "?=\n";
    $headers .= "MIME-Version: 1.0 \n" . 
                "Content-Type: text/html; charset=UTF-8; format=flowed \n".
                'From: Admin <' . $gonderen_mail . ">\n".
                "Content-Transfer-Encoding: 8bit \n". 
                'Bcc: ' . $gonderen_mail . "\n" .
                "X-Mailer: PHP \n";
    return mail($to, $subject, $message, $headers);
}

if ($_REQUEST['islem'] == 'yolla')
{
    $mailler = file($mail_dosyamiz);
    foreach ($mailler as $mail_adres)
    {
        $baslik = "";
        if (UTF8_mail("{$gonderen_mail} <{$gonderen_mail}>", $mail_adres, $konu, $mesaj))
        {
            echo "<font style='font:bold 12px verdana' color='red'>$mail_adres</font> <font style='font:bold 12px verdana' color='green'>adresine mail yollandı.</font><br />";
        }
        else
        {
            echo "<font style='font:bold 12px verdana' color='#cc0000'>$mail_adres</font> <font style='font:bold 12px verdana' color='red'>adresine mail yollanamadı.</font><br />";
        }
    }
    echo '<script>alert("Toplu mail yollama işlemi bitti!");</script>';
    echo "<br /><br /><a href='{$_SERVER['SCRIPT_NAME']}'>Geri Dön</a>";
}
else
{
    ?>
    <button onclick="location.href='<?php echo $_SERVER['SCRIPT_NAME']; ?>?islem=yolla';">Yolla</button>
    <?php
    //echo $mesaj;
}

Kullanımı;

$mail_dosyamiz = "maillist.txt";
$gonderen_mail = "hede@hodo.com";
$konu = 'Konu başlığı buraya';
$mesaj = 'Mesaj içeriği buraya (html kullanabilirsiniz)';

kısımlarını kendinize göre düzenleyin.