They've been using them since the very beginning of the season--including the pre-season games. Here's a recent article on their usage:Surfaces all over the place in the Patriots - Ravens playoff game. Near the beginning of the game they used a surface to show some video, BUT it was all pixelated and choppy. Very poor quality that could not have impressed anyone. Too bad.
They were all using a very cool heavy duty blue cover with a hand strap. Never seen that before.