The D95 supports PostScript and PCL. As most *nix applications support either plain text or PostScript printing, you should not need anything else. Just create a print queue to the printer and you will be in business. If the printer receives plain ASCII text it will use PCL to print it. If the application sends PS, the printer will recognise that and use its PS interpreter instead.
The only problem is with printer-dependent features (things like tray settings, duplexing, etc). Using cups you can access those features, and the only thing you need is the printer's PPD (postscript printer description) file. This is a text file that tells the driver what features the printer has, and what PS commands are used to access them. You can find the PPD on the Xerox web site (or, as it is a text file, you could extract one from the Windows or Mac PS drivers).