Same here. When I first heard about the N900/Maemo one of the first things I thought about was how cool it would be to be able to print directly from the phone to my bluetooth-enabled battery-powered portable printer.
I would hope it at least supports bluetooth. Some printers support bluetooth printing (the Kodak polaroid I believe is one of them) where I believe you just send a picture file over bluetooth and they have a certain amount of logic to translate and print it.