Popphoto.com has published a short article with a handful of details about how Nikon D2Xs cameras are rigged by NASA for use in space. 

One interesting note is that flash units will not work properly in the vacuum of space, so NASA has built a custom, pressurized housing for Nikon's SB-800 so it can be used on spacewalks. Apparently, the cameras themselves need only a special lubricant for use on spacewalks, but their useful life is limited by radiation in the space environment, which evidently quickly degrades sensors.