It'll replace the iOSD on a USB connected device (smartphone), but not any direct HDMI displays. It doesn't replace the functions of the current groundstation, and apparently they can't be used at the same time.
More info here, including feedback from a couple of members who have tested the Lightbridge already: viewtopic.php?f=22&t=9250
(Also just to clarify as this was posted in the Phantom 2 Vision thread - none of the above mentioned items will work with the Vision - Lightbridge will work with the P2, though...)