Zelda Wallpapers
In the never-ending quest to keep my desktop background covered in pretty pictures, I stumbled across a few useful Zelda-related fansites that have a ton of free wallpapers available. The first, Zelda Universe, has what I counted as just slightly less than a bajillion wallpapers ready to roll. Almost every Zelda game is represented, from Minish Cap to Ocarina of Time, Twilight Princess, Wind Waker and even the Oracle games. Most wallpapers are available in at least 800×600 and 1024×768 sizes, so no crummy stretching/cropping will be needed.
Zelda Infinite also has a great collection of wallpapers. These are organized by game and there seems to be a much larger selection, though the quality of both the image and the art can vary. Still, a few minutes browsing might net you something good for your screen.