There are 4 phillips head screws on the right side of the light (right side from the back of the light) including one on the grip, as well as 4 hex screws; 2 on each side (they are much larger than the phillips head screws). There is also another phillips screw on the left side of the grip, and two larger phillips screws on the back of the light, near the mode selector.
Also, there is a "hidden screw" underneath the rubber sleeve that goes over the head, so you will have to take that off first, then take out the screw (I believe there is only one, but I haven't opened it up in a while).
Be careful that you don't strip the screws; they don't have particularly hard heads.