The V-Screen is an add-on for Sony PSP consoles that's designed to make games appear in 3D. It's supposed to enhance "the perceived depth of the 2D screen image," and apparently will work with many games. It looks bulky in the picture, but the protrusions do fold down to a more compact state when not in use and act as a case for your PSP.
RealView Innovations, the company that will be making this product, doesn't seem to have a proper Web site yet, and no availability date and price has been given. We'll revisit this gadget when we get more concrete information.