Php mail function not working with godaddy.com

function emailHtml($from, $subject, $message, $to) {
$host = "localhost";
$username = "";
$password = "";

$headers = array ('MIME-Version' => "1.0", 'Content-type' => "text/html; charset=iso-8859-1;", 'From' => $from, 'To' => $to, 'Subject' => $subject);

$smtp = Mail::factory('smtp', array ('host' => $host, 'auth' => false));

$mail = $smtp->send($to, $headers, $message);
if (PEAR::isError($mail))
return 0;
else
return 1;
}