The feature is called Quick Glance. It is located in Settings -> Motion -> Quick glance -> Check this box. You simply, and apparently slowly, swipe your hand over the top of your phone while it is sitting flat on a surface. The screen comes on and shows you missed calls, messages, battery life and a few other key elements. How this is any faster or better than just hit your power button real quick is beyond me, but it is still pretty cool. Take quick look at SamMobile trying to make it work.