Easy Photoshop Stencil
<object width="445" height="364"><param name="movie" value="http://www.youtube.com/v/GIFRFZlBjIk&hl=en&fs=1&rel=0&border=1"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/GIFRFZlBjIk&hl=en&fs=1&rel=0&border=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="445" height="364"></embed></object>
Image
Find yourself an image. I just happened to find a zombie image with no background which made it easier to remove the background. Use either the wand tool or the quick selection tool and delete the background.
Desaturating
Go to Image/Adjustements/Desaturate and click. Now your photo will be black and white.
Threshold
Go to Image/Adjustments/Threshold and move the arrow until your image is completely solid black or whatever color you had chosen.
Brains!
Now print it and cut it out and go put it up everywhere!