After spending time trying to avoid installing anything on Windows XP to print to an Airport Extreme shared printer, I broke down and installed Bonjour for Windows 1.0.5. It was a small download, and it appears to only install a helper application which setup the TCP/IP printer port(s) for your printer(s). It immediately found the shared printers on the network and had them up and running within seconds.
Printing now seems to work flawlessly from Windows XP to my Brother Laser Printer.
