hook_mail_alter() implementation

gistfile1.php

/**
 *  Implements hook_mail_alter().
 */

function mymodule_mail_alter(&$message) {
        if (($message['id'] == 'contact_page_mail') || ($message['id'] == 'contact_user_mail')) {
                $message['headers']['Reply-To'] = $message['from'];
                $message['body'][2] = $message['body'][1];
                $message['body'][1] = 'Reply to this message using: '.$message['from'];
                $message['from'] = 'noreply@example.com';
                $message['headers']['From'] = $message['from'];
                $message['params']['mail'] = $message['from'];
  }
}