Wow. Honestly, wow.
Google Earth shows you our world from satellite height down to the cars parked in your driveway.
Google Sky knits together astronomical images into a navigable universe, as seen from Earth.
As a failed astrophysicist, this one blows my mind. I like features like the 'planet slider', the 'users guide to galaxies', etc. I just spent way too much time wandering around the universe. Virtually. I am drooling. I am actually drooling. I also love the awe inspiring banality of the naming scheme. Google "earth". Google "sky". Next up, Google "Air". You are breathing it. And they want it back.
Claudia Cristovao from W+K Tokyo found this article outlining the features.
Here's a quick video demo from Google about their new application:
download it here.