I am currently working on a game that will use the Act-Labs lightgun, You program it as a mouse device not joystick, the lightbeam is the cursor and the trigger is left click. It is 3dgs compatible and there is a free SDK download here
http://www.act-labs.com/gun1.htmlook in the lower lefthand corner of the page.
The makers of the gun have visited this forum a few times trying to generate interest in developing games for the gun. I have been in contact with them (via email) and they will sell your game via their online store once it is done.
