I just updated to 10.6, and my printer driver did seem to be supported. Rather than trying to install the old driver, I came across a blog post that said to use a driver from another brand of the same printer.
For my Fuji Xerox Docuprint 203A, I used the Brother HL-2030, which has the same printer icon and setup. This worked perfectly for me.
[robg adds: I can't easily test this one here, but you'll want to do some preliminary work with Google to find out if your printer is available under different names from other companies.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20090831153141163