How can I make a Lexmark Z12 printer to work in a Unix enviroment (Linux,FreeBSD, OpenBSD)?

Check out page 1 (http://www.lexmark.com/beta/) and page 2 (http://www.lexmark.com/beta/available_software.html) from Lexmarks web site. They have linux drivers for beta testing.

I'd send them an email, and ask them what you need.