Electrical Grounding in ATX Cases?

FoxMulder asks: "I'm constructing a clear case made of Plexiglas for my new athlon machine. I don't know for sure how the grounding system on ATX power supplies work, but I am wondering what I can do to properly ground my machine without the use of the metal case that is so classicly accepted. I also am interested to find out which parts of the machine should be grounded, and to what. I've had a little bit of an electric bill problem when my last computer with an AT power supply wasn't grounded properly."