Zend FR

$mail = new Zend_Mail();
$mail->setSubject('Test');
$mail->setFrom('hello@ex.com');
$mail->setBodyText ( "" );

$at = $mail->createAttachment($txtFile->toString(), 
                                'text/plain', 
                                Zend_Mime::DISPOSITION_ATTACHMENT, 
                                Zend_Mime::ENCODING_8BIT);

$mail->addTo ( "hi@you.com" );
$mail->send();