Here's a prototype screen interface from Microsoft which was demoed at the CEBIT 2006 conference. It's very similar to the interface from the movie Minority Report. I believe they are using a rear projector (though it's possible they are using an LCD). Basically there is a piece of glass with the display on it and then behind the glass is a motion sensor which tracks the user movements (I believe). There is either an LCD sandwiched in between two pieces of glass or a rear projector. I also think this is the interface that Robert Scoble talks about in this interview.
Check out the video of the interface ala Minority Report below or click over and view it on the host site.