These are pics from the same bike that is pictured on page 4 of this thread. Pictured here is my first attempt at a studded tire. Seeing as we just got another 5 inches of snow on top of the foot-plus that we already had, it looks as though it will be useful.
Hope these pics work...

I made this with 1/2 and 3/4 inch wood screws drilled through the tread of the tire. The inside of the tire was then duct-taped to protect the tube, and an old tube was slized open and layed on top of the duct-tape to add more protection. So far, it has worked fine - the only problem was mounting it. The effort needed compared to a regular tire was much more. It grips well, and the screws through the side knobs hook up well.