SWITCHING FROM WARP TO FREE TRANSFORM (AND BACK AGAIN)

If you're using CS2's Warp Image feature (which is accessed by pressing Command-T [PC: Control-T] to bring up Free Transform, then Control-clicking [PC: Right-clicking] inside the Free Transform bounding box and choosing Warp from the contextual menu), there's a good chance you'll need to resize the image once you start warping it. If that happens, there's a button you can click that will switch back to Free Transform. It's near the top-right corner of the Options Bar, and clicking the button will toggle you between Warp and Free Transform.