[Zope] PUT_Factory question

Hi ! I have read here and there a few messages talking about "PUT_Factory" scripts, which seem to enable us to create given objects types from informations transfered via HTTP or FTP "PUTs". Where could I find informations about this method ? Does it have to be implemented as a simple DTML Method, as a Python script or as an external method ?? Any information would be really usefull to me... Thanks, Thierry