How do you load PHPMailer into or where do you get PHPMailer to use in this instance

<?php
require_once('class.phpmailer.php');
//
$mail             = new PHPMailer();

$mail->IsSMTP(); // telling the class to use SMTP
$mail->Host       = "ssl://smtp.gmail.com"; // SMTP server
$mail->SMTPDebug  = 1;                     // enables SMTP debug information (for testing)
                                           // 1 = errors and messages
                                           // 2 = messages only
$mail->SMTPAuth   = true;                  // enable SMTP authentication
$mail->SMTPSecure = "ssl";                 // sets the prefix to the servier
$mail->Host       = "smtp.gmail.com";      // sets GMAIL as the SMTP server
$mail->Port       = 465;                   // set the SMTP port for the GMAIL server
$mail->Username   = "gmail@gmail.com";  // GMAIL username
$mail->Password   = "pass1";            // GMAIL password

$mail->From('gmail@gmail.com');

//$mail->AddReplyTo("gmail@gmail.com");

$mail->Subject    = $subject;

//$mail->AltBody    = "To view the message, please use an HTML compatible email viewer!"; // optional, comment out and test

$mail->Body=$body;

$mail->AddAddress($email);

//$mail->AddAttachment("images/phpmailer.gif");      // attachment
//$mail->AddAttachment("images/phpmailer_mini.gif"); // attachment

if(!$mail->Send()) {
  echo "Mailer Error: " . $mail->ErrorInfo;
} else {
  echo "Message sent!";
}

?>