I finally found the solution, and now my windows can print wid full functionality.
Here's the procedure
1. On the Mac (the one that the USB printer that you want to share is connected to), go to the Sharing
preferences pane and ensure Printer Sharing and Windows Sharing are both turned on.
2. From your browser go to http://127.0.0.1:631 - this is the web interface to CUPS. When asked to
enter a password, login with your Mac OS X administrator account.
3. Go to the Printers tab and add a new printer (yes, in addition to any existing printer configuration
that already exist for the same printer). Choose a name that?s short and descriptive (no spaces).
Let?s call it ?windowsprinter?.
4. When asked to select a device, select USB printer.
5. You?ll be asked for a Device URI. To find out, open up a terminal and type lpinfo -v. You should see
your USB printer coming up. Mine came up as ?direct usb://Epson/Stylus Photo%201280?
serial=CN516851RPUN?. Copy and paste this (without the ?direct? part - i.e., I?d have copied
?usb://Epson/Stylus Photo%201280?serial=CN516851RPUN?) into the ?Device URI? field.
6. Select a ?Make? of ?Raw?. Keep going until the printer is added.
7. You?re done configuring from the Mac.
8. Now go to your Windows machine and add a new printer (Control Panel -> Printers and Faxes).
Select ?A network printer? ?. Don?t browse for the printer, you will enter its IP address directly in the
?URL? field. Enter ?http://your.macs.ip.address:631/printers/windowsprinter? (replacing
?your.macs.ip.address? with your Mac?s IP address and ?windowsprinter? with the short name you gave
your printer).
9. Now, all that?s left is to install the correct Windows printer driver on the Windows machine.