Stellarium is a free open source planetarium for your computer. It shows a realistic sky in 3D, just like what you see with the naked eye, binoculars or a telescope. It is being used in planetarium projectors. Just set your coordinates and go.
The sun is down, the stars are visible. Stellarium 0.10.0 has extensive star catalogs. 600,000 are included by default, but you can even download extra catalogues to see up to 210 million stars. This work was done by our team member Johannes.