The usage, for anyone that got a little confused as I did, is to take the last part of any Zend_Validate_XYZ and use the XYZ as the string in any addValidator chain like so: ->addValidator('XYZ') so for example, to validate an email address use the Zend_Validate_EmailAddress class or ->addValidator('EmailAddress') on the elements variable
Don't forget that the second parameter is whether a failure should break the chain. True breaks the chain, False does not. So, if we wanted to validate an Alpha only field and then an AlphaNumeric field but NOT break if the Alpha field !isValid() then:
->addValidator('Alpha', FALSE)->addValidator('AlNum', TRUE)