OK, after looking at the picture again, it looks like the visor will be MOVABLE. Check out the little groove/notch cut into the inside of the viewfinder thing. It makes it look like it can flip up over the helmet, with the groove gliding over the long ridge across the center of the helmet.
I noticed that too Matt. It is exciting to see more and more pics of Episode III, and I really like the fact that they're showing a "hybrid" of sorts of the Storm and Clone troopers. I do kind of hope that visor will be movable, and I could definitely see them doing something like Scott mentioned...with the "reveal" of the face that looks like a Stormtrooper....that would be pretty cool.