gistfile1.aw

<?php

/**
 * Form submit...
 */
function my_module_submit($form, $form_state) {
  $email = $form_state['values']['email'];
  $message_type = $form_state['values']['message_type'];
  $params = array('form_values' => $form_state['values']);
  drupal_mail('my_module', $message_type, $email, language_default(), $params);
}

/**
 * Implementation of hook_mail().
 */
function my_module_mail($key, &$message, $params) {
  switch ($key) {
    case 'message_type':
      $message['subject'] = $params['form_values']['subject'];
      $message['body'][] = $params['form_values']['message'];
      break;
  }
}