Can't print to printers on Windows XP machines

I have a Mac Mini on a network with three XP machines, each with a printer: HP OfficeJet 600, Epson Stylus 600, and Lexmark Z65. Networking works for file access from both directions, and the Mac can see the printers, but printing fails. I downloaded Bonjour on an XP, but it is apparently only for printing to the Mac. I want to print to at least on of the XPs from the Mac. Any suggestions? This seems enormously complicated and difficult to do what is very simple in the Windows world. My impression had been that the Mac had this wonderful "zero" difficulty networking, but it is anything but that.
Since you can see the printers, it is a matter of selecting the correct printer driver.

What OS version is on the Mac? You may need to install Gimp Print for a driver that works.
I suggest trying the beta. The drivers work well enough for me. I share an Epson RX600.
Although it is good to read about Gimp-Print at that site, if you have Panther (10.3) or Tiger (10.4) installed, Gimp-Print is already installed on your computer.