Okay... Here's how it works...
You use it as you would a normal controller. Your X/Y screen coodinates are as if the gun was the left thumbstick. The trigger is button A. If LeftSitck.x = 0 and RightStick.y = 0, you're either not pointing at the screen, or you're pointing EXACTLY in the middle. Most likely you're off screen.
Don't use a deadzone for this.
It is REALLY easy to program for the gun.
BTW - Bought another gun today from Circut City. Woo hoo... Two play gun games.