extend CCK-fields with custom formatters

We can create new custom formatter for CCK fields using hook_field_formatter_info(), below is the example

/**
* Implementation of hook_field_formatter_info().
*/function myModule_field_formatter_info() {
  $formatters = array();
  if (module_exists('filefield')) {
      $formatters['myFormatter'] = array(
        'label' => t('My Formatter'),
        'field types' => array('filefield'),
        'multiple values' => CONTENT_HANDLE_CORE,
      );
  }
  return $formatters;
}
/**
* Theme function for myFormatter from hook_field_formatter_info.
* @param $element
*   an array of formatter info and the item to theme. look in $element['#item'] for the field item to theme.
*/function theme_myModule_formatter_myFormatter($element) {
  return "themed element"; 
}
/**
* Implementation of hook_theme().
*/function myModule_theme($existing, $type, $theme, $path) {
  return array(
    'myModule_formatter_myFormatter' => array(
      'arguments' => array('element' => NULL),
    ),
  );
}?>