Stellarium - Stellarium is a free open source planetarium for your computer.
SpaceVR - Explore space with Oculus Rift (pre-launch)
Sky Guide - A window to the stars has never been more beautiful and easy to use.
The Size of Space - An interactive visualization of the universe
SkyView - SkyView is powerful, easy-to-use app that answers questions about stars, constellations, and more.
Space Telescope - Explore the universe on Apple TV