Do the standards:
Install the Printer on your print server from the Manufacturer's CD that comes with HP8150N. Install all the three or so drivers (PCL and PS). I have extensive experience with HP8100DN, and I hope HP8150N's installation and configuration would be more or less the same.
During installation it would create a port and ask if you want to share this printer or not. You know what to answer.
I believe you have already done this. Next, on all the client workstations (Win2K and WinNT) add these shared printers as "network print servers". The wizard should download the appropriate drivers from the print server.
When you are through all these formalities, you should be able to print both from the server and the workstations. If you are having problems, please come up with specifics, I mean error messages.
Hope this will help.
Mubashir