I've got a set under my dash that I picked up from Autozone with the shitty cigarette lighter connector, cut them off, wired them to a switch which gets its power from another wire in the fuse box.
Mounted the tubes using plastic zip ties through some of the holes in the metal supporting the dash/steering column. I also removed the valence cover underneath the passenger side of the car to make room for the tube, as there isn't much room under the passenger side for a neon tube. (Damn you LED users!) If you go this route, just remember to keep everything you remove simply for resale value if (god forbid!) you are forced to sell your PT in the future.