I have a relatively old NEC printer (NEC SuperScript 870) hooked up to my desktop machine. It has PCL instead of PostScript so it wasn't a surprise to find that OS X Tiger didn't come with a driver for the printer. But, with a bit of searching, I found that Gutenprint, a massive bundle of print drivers for Mac and *nix, had a driver for my printer.
I installed Gutenprint 5.0 for OSX binary (dmg, source) but when I clicked on the printer model list popup in the OS X Print & Fax preference panel, I didn't see NEC. Reading the brief Gutenprint how to guide, I found that the Option key needs to be pressed while clicking on the printer model list popup to see the full list of drivers. Stupid but I didn't have time to rant so I did as instructed and, sure enough, NEC showed up in the list. Selecting that resulted in a list of NEC printers supported, one of them being SuperScript 870. After printing a few test pages, I can say the Gutenprint driver works excellently for my printer.