<?php

require_once 'path/to/SwiftMailer/lib/swift_required.php';

$transport = Swift_MailTransport::newInstance();
# Create the Mailer using your created Transport
$mailer = Swift_Mailer::newInstance($transport);
# Create the message
$msg = Swift_Message::newInstance();
# Give the message a subject
$msg->setSubject($_POST['subject']);
# Set the From address with an associative array
$msg->setFrom(array($_POST['sender_email'] => $_POST['sender_name']));
# Give it a body
$msg->setBody($_POST['message'], 'text/html');

$failedRecipients = array();
$numSent = 0;
$to = array(
    'recipient_1@gmail.com',
    'recipient_2@yahoo.com' => 'Recipient 2',
    'recipient_3@hotmail.com',
    'recipient_4@gmail.com' => 'Recipient 4',
    'recipient_5@yahoo.com'
);

foreach ($to as $address => $name) {
    if (is_int($address)) {
        $msg->setTo($name);
    } else {
        $msg->setTo(array($address => $name));
    }

    $numSent += $mailer->send($msg, $failedRecipients);
}

echo $numSent > 0 ? 'SUCCESS' : 'FAILURE';

?>

$msg->setBody($_POST['message'], 'text/html');

$msg->setBody(stripslashes($_POST['message']), 'text/html');