I'd like to start by saying that there are several threads on this, so I'll just explain in a quick overview sort of way, there may be a few steps I summarize or skip because they are very easy, but if you need some clarification, ask here.
ok, on your Mac, go to the System Preferences and select Sharing. Click on the Services tab and check the box next to Windows Sharing.
Next, go to your Windows PC and pull up the Network Neighborhood or the link that says 'View workgroup computers'. Click on the icon for your Mac and you should see entries for each printer you are sharing on your Mac. Click on the printer you wish to use and you will be presented with the Add Printer Wizard.
No matter what kind of printer you have, tell the Wizard to use the Apple LaserWriter driver for black & white printers or the Apple Color LaserWriter for color printers. This will ensure that Windows will generate good PostScript code that will be translated correctly to your printer.
You should now be able to print from Windows to your Mac-connected printer. There are a couple of other steps that you may need to take if you are running a version of OS X previous to 10.3 Panther, but again, if you need more clarification, post here.