function fixed_field_help($path, $arg) {
 switch($path) {
  case "admin/help#fixed_field":
   /** @ToDo http://drupal.org/node/632280 */
   return '<p>'.  t("Displays a field with fixed content") .'</p>';
   break;
 }
}

/**
 * Implements hook_field_info().
 */
function fixed_field_field_info() {
 return array(
  'fixed_field' => array(
  'label' => t('Fixed'),
  'description' => t('A fixed field'),
  ),
 );
}