Basically it's made out of MDF (
http://en.wikipedia.org/wiki/Medium-density_fibreboard), 20mm thick, and then painted on with lacquer. The signs are made out of photographic paper (I ordered a custom-made poster for that).
I made a drawing of the measurements, see here (
http://img518.imageshack.us/img518/5...rcutoutvd7.jpg). I first built the basic frame (i.e. without the grey side panels, which are just attached from the outside), and afterwards attached the front panels, back, and side panels.
HTH

And happy building.