"The WorldWide Telescope (WWT) is a rich visualization environment that functions as a virtual telescope, bringing together imagery from the best ground and space telescopes in the world for a seamless, guided exploration of the universe.
WorldWide Telescope, created with Microsoft's high-performance Visual Experience EngineTM, enables seamless panning and zooming across the night sky, blending terabytes of images, data, and stories from multiple sources over the Internet into a media-rich, immersive experience."
"Google Sky - Traveling to the stars has never been easier
To help you explore the far reaches of our universe, we have teamed up with astronomers at some of the largest observatories in the world to bring you a new view of the sky. Using Google Maps this tool provides an exciting way to browse and explore the universe. You can find the positions of the planets and constellations on the sky and even watching the birth of distant galaxies as seen by the Hubble Space Telescope.
We are particularly excited about the ability to view the universe at different wavelengths, to see how it would look if our eyes worked in the x-rays or infrared. As you explore these new layers, play with the transparency to blend between the different wavelengths and see how different parts of the universe light up at different wavelengths.
If you are interested in what's happening on the sky tonight or over the next few months then check out the podcasts from Earth and Sky or search for the position of your favorite planet."