Take a look at Wikisky, an impressive Web 2.0 project from Canada.
Astronomy is one of those fields that has always been obsessed with catalogues--from Hipparchus to modern-day systems, everything needs to be assigned an identity. Nowadays astronomers often don't know where in the sky their objects are; ask them about it and they know the catalog number, but not the constellation.
With the power of cataloging comes the ability to analyze, map, and link. Wikisky does this nicely with the easy user interface that we all use: Google Maps.
In addition, once you've found an object you're interested in, Wikisky will query the Astrophysics Data System for articles with your object mentioned in the text. This at the moment needs a little work to bring up more relevant articles.
I see Sloan Digital Sky Survey data, and also a lot of amateur CCD images; really good imagers add World Coordinate System headers to their FITS headers, and it seems the system must do something with those to grab the right images that contain your object. You can also ask it to query the Digitized Sky Survey for you and pick up an image.