I've made some success with this

Zend_Loader::loadClass('Zend_Date');
$oDate = new Zend_Date();
$strDate = utf8_decode($oDate->toString("EEEE, dd 'de' MMMM 'de' YYYY"));


Take a look inhttp://framework.zend.com/manual/en/zend.date.constants.html
and
Zend Framework: Documentation