Here's the design I came up with for a birthday gift this week. It's a simple bird design to trace and stencil using the freezer paper method.
Download this file, and print it out. It is complete with directions.
It's a publisher file. If you try to download it and can't, please let me know. I've never tried this before.
To make a two color, layered image, trace the design onto two different sheets of freezer paper. Then darken only the section of the stencil that you want painted in each color. Then only cut the darkened areas of each.
Remove the first stencil and wait until the first color is dry before adding the overlapping color. I did the bird body only in blue, the stem only in brown, and everything else was in both colors. The effect was cool since the two stencils didn't line up perfectly, and both colors showed through.
It would be great if I had a picture of the finished product, but true to form I wrapped it up and gave it away before I thought to take a picture. Of course.