From The New York Times:
The skies may be the next frontier in travel, yet not even the wealthiest space tourist can zoom out to, say, the Crab Nebula, the Trapezium Cluster or Eta Carinae, a star 100 times more massive than the Sun and 7,500 light-years away.
But those galactic destinations and thousands of others can now be toured and explored at the controls of a computer mouse, with the constellations, stars and space dust displayed in vivid detail and animated imagery across the screen. The project, the WorldWide Telescope, is the culmination of years of work by researchers at Microsoft, and the Web site and free downloadable software are available starting on Tuesday, at www.WorldWideTelescope.org.
More here.