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.
What's new in this version: Version 0.12.1 has re-packed star catalogs (Hipparcos and Tycho-2)and have closed over 30 bugs in the core application and plugins.