With OS10.4, the only problem I had with printing with my networked (via AirportExtreme) Brother 2070N was when my G4PB would have a 10.x address instead of a 192.x address. Not so with Leopard and the new MBP. I finally got tired of walking to the office for a USB print, and Google helped me find this helpful post on LiveJournal. (tip)

The problem is that Brother printers aren’t talking “Bonjour” under Leopard — dunno if it’s Apple’s fault or Brother’s.

• You have to change your settings
  Protocol: HP Jetdirect-Socket
• You have to know the IP address of the printer
  (I have a Windows utility for this but haven’t found a Mac one)
• You have to change the driver
  Brother – CUPS

Brother has directions (pdf). In Leopard, printers are managed through System Preferences. “Add” or “delete” a printer using the “+/-” icons on the print/fax preferences panel. You can access the print/fax preferences panel directly using the print-dialog box.