I'm bumping this thread because I just replaced a 6.01 box running CUPS (due to hard drive failure) with a 7.0b8 box. One of the issues with this network was the necessity of printing from Mac OS 8 and 9 clients to printers shared from Windows XP. I couldn't get LPRng on 6.01 to do that correctly (though operator error shouldn't be discounted) so I'd installed CUPS on the SME server and it worked a treat until the crash.
I thought I'd see how 7.0 handles such things; I had already installed Print Services for Unix on the XP box long ago, so I set up a network printer in 7.0 with the XP's IP address and the share name as the queue name. Voila, the 7.0 shared printer showed up in the Mac Chooser and printing worked first time.
Brilliant work, development team! Many, many thanks.