Print From Your Computer : Macintosh Printing (Mac OS X 10.5 and 10.6)

Select Page Setup Options
Depending on your application, you may be able to select the paper size and orientation settings, and adjust the size of your printed document or photo, from the Print window.
If you don’t see these settings in the Print window, check for them in your application before printing. For example, you may be able to select them by opening the File menu and selecting Page Setup.
Select the Paper Size setting for the paper you loaded. A custom option is also available so you can create a custom paper size.
If you want to print a borderless photo, select the paper size with a Sheet Feeder - Borderless option.
For borderless photos, make sure you loaded a compatible borderless paper size and type.
Choose a portrait or landscape Orientation option for your document or photo. (Choose landscape for envelopes.)