USNO PMM Star Catalogs
USNO is making the USNO-SA2.0 catalog (54,787,624 stars in all on one CD-ROM) available for free. The full USNO-A2.0 catalog (526,230,881 stars on 10 CD-ROMs) is also available provided you can provide a brief explanation of why USNO-SA2.0 is not sufficient. That's information on over half a billion stars!
http://www.nofs.navy.mil/projects/pmm/catalogs.html

The Hipparcos Space Astrometry Mission
home page, site guide, research tools, news and results, the catalogues, education, visual results, further information, the future, animations.
http://astro.estec.esa.nl/Hipparcos/

The Hipparcos Catalogue
home page, site guide, research tools, news and results, the catalogues, education, visual results, further information, the future, animations.
http://archive.ast.cam.ac.uk/hipp/hipparcos.html

GSC - The Online HST Guide Star Catalogue
home page, site guide, research tools, news and results, the catalogues, education, visual results, further information, the future, animations.
http://arch-http.hq.eso.org/gsc/gsc-query2.html

White Dwarf Database
An electronic database of the white dwarf stars.
http://procyon.lpl.arizona.edu/WD/

The 50 Nearest Stars
Table with details about the 50 nearest stars. Names, distances, constellations, spectral types, magnitudes and coordinates.
http://www.cosmobrain.com/cosmobrain/res/nearstar.html

The Double Star Library
The Double Star Library hopes to be a means by which various types of binary and multiple star information can be easily disseminated among binary star astronomers in IAU Commission 26 and related commissions.
http://www.chara.gsu.edu/CHARA/double.html

Nstars Online Spectra
A spectroscopic survey of 3600 nearby stars within 40pcs earlier than M0. Contains real-time spectral plots, and coordinate lists. Also MK standards.
http://stellar.phys.appstate.edu

Astrometric holdings in ADC Archives
Data sets in the Astronomical Data Center's Astrometric, and Positional data holdings. Contains site map, science data, news, and feedback.
http://adc.gsfc.nasa.gov/adc/adc_cat1_holdings.html

Catalog of White Dwarf Stars McCook and Sion
A catalog of spectroscopically identified white dwarf stars, by George P. McCook and Edward M. Sion
http://www.willbell.com/software/hypersky/wd1987.htm