This is actually a really simple process and once you've done it, you can do it forever. Pinhole cameras can be made out of any canister that is dark inside. I used a little food tin, and because it is shiny and metallic, i had to paint it black. I think I would suggest it of any canister used, though.
Materials needed for this project:
your canister of choice, preferably with a lid. (mine was a food tin with cardboard cover.)
black spray paint (the cheapiest kind, 97 cents from home depot)
light sensitive paper or film (I used Polaroid 300 available on Amazon.com)
a dark dark room
a hard flat surface to role on
Step 1: Paint
Just go ahead and paint the inside of the canister black. I did two coats just to be sure and cover up all the shiny bits. We don't want ANY reflective surfaces on the inside of the camera.
Step 2: The Pinhole
Make your pinhole and "lens cover". I used three layers, actually, of duct tape, because, as it turns out, duct tape isn't so dense. It wasn't a big deal though.
Step 3: DARK ROOM
Now you need to go into that dark dark room. When you're in there, you have to put your film into your camera and tape it in there so it won't move. With the film I used, I had to make sure I was putting the right light sensitive part towards the light and not the back of the camera. If you're using the same film I used, the trick is finding the bump at the top of the film. Finding that with your fingers will tell you that's the light sensitive side, and its the top of the photo, which needs to go on the bottom, because your image will be flipped as physics works its magic.