Zend Framework 1.10.9 Manual

//We suppose that character encoding of strings is UTF-8 on PHP script.
function myConvert($string) {
    return mb_convert_encoding($string, 'ISO-2022-JP', 'UTF-8');
}

$mail = new Zend_Mail('ISO-2022-JP');
// In this case, you can use ENCODING_7BIT
// because the ISO-2022-JP does not use MSB.
$mail->setBodyText(
    myConvert('This is the text of the mail.'),
    null,
    Zend_Mime::ENCODING_7BIT
);
$mail->setHeaderEncoding(Zend_Mime::ENCODING_BASE64);
$mail->setFrom('somebody@example.com', myConvert('Some Sender'));
$mail->addTo('somebody_else@example.com', myConvert('Some Recipient'));
$mail->setSubject(myConvert('TestSubject'));
$mail->send();