Assuming (stop snickering) that you are using the web interface to manage CUPS (
http://localhost:631 ) this should do the trick:
1.) Click the "Printers" graphic in the navigation bar.
2.) On the "Printer" page click the "Add Printer" icon
3.) You should then be required to enter a password
4.) Now, enter the Name, Location, and description of the printer and click "Continue". These are just text labels so you don't have to worry about getting the exact model type
5.) In the dropdown for device, select AppSocket/HP JetDirect and click "Continue"
6.) Now in the "Device URI" textfield type in "socket://XXX.XXX.XXX.XXX" replacing the X's with the IP addy of the printer. [[Continue]]
7.) Make should be the make of the printer. [[Continue]]
8.) Model should be the model of the printer [[Continue]]
10.) And that should be done
A few things to make sure you have installed are
hpijs (if it's an HP printer or if recommended on the CUPS website for your printer)
espgs
gnu-gs-fonts
Good Luck