Free Online Telescope, K-12

http://www.worldwidetelescope.org/Home.aspx
The WorldWide Telescope (WWT) is a Web 2.0 visualization software environment that enables a computer to function as a virtual telescope—bringing together imagery from the best ground and space-based telescopes in the world for a seamless exploration of the universe.

Users may choose from a growing number of guided tours of the sky by astronomers and educators from some of the most famous observatories and planetariums in the country. You can pause the tour, explore on your own (with multiple information sources for objects at your fingertips), and rejoin the tour where you left off.

View the sky from multiple wavelengths. See the x-ray view of the sky and zoom into bright radiation clouds, and then crossfade into the visible light view and discover the cloud remnants of a supernova explosion from a thousand years ago. Switch to the Hydrogen Alpha view to see the distribution and illumination of massive primordial hydrogen cloud structures lit up by the high energy radiation coming from nearby stars in the Milky Way. Seamlessly pan and zoom from aerial views of the moon and selected planets, as well as see their precise positions in the sky from any location on Earth and any time in the past or future.