Hello, hello!
 

This is a great idea, because everyone is pretty much forced to look at it when they use the toilet! Our college did a "Behind Closed Doors" campaign where basically, we printed out sheets of paper with facts on smoking, lung cancer, and things related to it, then we put it up on the back of every bathroom stall on campus. You can either use those plastic sheet covers that you normally use for pages in a binder, or buy plastic pannels that can be mounted to the wall. Just sketch up a regular 8.5 x 11 paper and make it eye-catching with colors and big fonts! Hope this helps!