This is for Debian.

Install the packages

apt-get install foomatic-db cupsys foomatic-filters-ppds

Configure the printer

• Go to http://127.0.0.1:631/ in your favorite web browser
• Click "Printers"
• Click "Add Printer"
• Name it whatever you want
• Device: AppSocket/HP DirectJet
• Then, socket://hostname:9100
• Make: Lexmark
• Model: Lexmark Optra Color 1200 Foomatic/Postscript

Now print a test page to test!

Configuring firefox

Go to File > Print > Properties and change your "Print command" to:

lp

Fire off another test print!