One of the few reasons I ever wanted to root my first Android phone in the first place was because doing so allowed me to take screenshots of any screen I wanted, at any time. I always felt that should be a built-in feature and shouldn't require rooting my phone, but HTC has changed all that. Even though they've made it difficult to root the Rezound (or at least that's how it seems, seeing as we still only have temp root), they at least threw us a bone when they implemented a built-in screen grabbing option.
To take a screenshot on your HTC Rezound, simply gently hold down the power button and tap the home key at the same time. That's it! Your screen will flash and read "screenshot saved to Camera shots" as in the picture below. You can access the picture by viewing your photo gallery as you would with any other picture taken by your camera.