No. You don't have to mess with the screen at all, and once you've gone thru the 1-time setup I described, you simply long-press the volume-up button on the left side of the phone to turn on the light. To turn it off, just tap the volume-down (or let it time-out to whatever you set it to when configuring). Once you go thru the 1-time setup, you don't need to wake up the phone at all… just press the button like a real flashlight.
Help yourself while helping me: Sign up with Dropbox and we both get 250MB extra space. Thanx!