How can I control the use of HP printers

I am responsible for four child computer labs. In each lab, I have a HP Color Laser which is connected to the network with Jet Direct cards. As the laser cartridges are rather expensive I would like to control who prints what. I don’t want the children to just arbitarily print every new web site that they go to. There is an adult monitor present in the lab at all times. All the computers are running Windows 2000. Is it possible to password protect the printer so that if a child has a validneed to print, that they have to ask the lab monitor for permission and the lab monitor then enters a password allowing the print job to happen? Is it possible to run a “print as administrator” command or some other command that will work.