Aladin sky atlas
From WolfWikis
Available from the CDS at http://aladin.u-strasbg.fr/aladin.gml.
From the Aladin site:
Aladin is an interactive software sky atlas allowing the user to visualize digitized astronomical images, superimpose entries from astronomical catalogues or databases, and interactively access related data and information from the SIMBAD Astronomical Database, the VizieR Service and other archives for all known sources in the field.
A tutorial is available at http://aladin.u-strasbg.fr/tutorials/cds.gml.