E.T.
backyardchickens.com has blueprints from members as well as pictures of coop ideas.
But you really don't need a coop blueprint. Just figure out how large you want to make your coop and look for a shed or a playhouse blue print, since a chicken coop is basically just a shed/outbuilding that chickens live in.
And... be absolutely certain that you build your coop large enough since you can't go back and fix it. You will need 4 sq feet of floor space per chicken in the coop, and 10 sq feet of space per chicken in the outdoor chicken yard. If you do less, you may have problems with chickens fighting or other behavior problems.