URLs (Uniform Resource Locators) provide the address information needed to make a link with a World-Wide Web site. A popular user interface to the WWW is NCSA Mosaic. A number of lists of astronomical resources have been established, and coordination between those maintaining these lists has been undertaken by a group calling itself the ``AstroWeb Consortium''. Current members are: Jackson (STScI), Wells (NRAO), Koekemoer (Mount Stromlo), Egret and Heck (Strasbourg Observatory), and Adorf and Murtagh (ST-ECF). The AstroWeb Consortium has formed a common resource listing, and assembled various tools - in particular, automated submission procedures for new URLs, and automated checking procedures to verify that URLs still respond to accesses as expected. Currently, more than around 1000 astronomically-relevant URLs are available. At URL http://fits.cv.nrao.edu/www/astronomy.html, these astronomical resources are categorized under: Observing Resources, Data Resources, Organizations, Software Resources, Publication-Related Resources, People-Related Resources, Various Lists of Astronomy Resources, Astronomical Imagery, and Miscellaneous Resources.
A short list of URLs for sites which support user services - archive research, or observing - is given below. No guarantee can be made that required information will be found at these sites. However, the momentum behind the World-Wide Web is currently very great, and the information available through Mosaic (or other browsers) is growing constantly in quality and quantity. The World-Wide Web is thoroughly compatible with other network-based access mechanisms: WAIS, Gopher, FTP, telnet, etc., and in fact provides a common user interface to all of these.
ADS (NASA Astrophysics Data System): http://adswww.harvard.edu/adswww/adshomepg.html
CADC (Canadian Astronomy Data Center): http://cadc.dao.nrc.ca/CADC-homepage.html
CDS (Strasbourg Data Center): http://cdsweb.u-strasbg.fr/CDS.html
CEA (Center for EUV Astrophysics): http://cea-ftp.cea.berkeley.edu/HomePage.html
CTIO (NOAO Cerro Tololo Interamerican Observatory): http://ctios2.ctio.noao.edu/ctio.html
ESIS (European Space Information System): http://mesis.esrin.esa.it/html/esis.html
ESO (European Southern Observatory): {http://www.hq.eso.org/eso-homepage.html
HEASARC (High Energy Astrophysics Science Archive Research Center): http://heasarc.gsfc.nasa.gov
NASA (National Aeronautics and Space Admininstration Information Services): http://hypatia.gsfc.nasa.gov/NASA_homepage.html
Mount Stromlo and Siding Springs: http://meteor.anu.edu.au/home.html
NRAO (National Radio Astronomy Observatory): http://info.aoc.nrao.edu/
NOAO (National Optical Astronomy Observatories): http://www.noao.edu/noao.html
NASA (NASA Online Information): http://mosaic.larc.nasa.gov/nasaonline/nasaonline.html //
National Solar Observatory: http://argo.tuc.noao.edu/
Planetary Data System: http://starhawk.jpl.nasa.gov/pds_home.html
ST-ECF (Space Telescope - European Coordinating Facility): http://ecf.hq.eso.org/ST-ECF-homepage.html
STScI (Space Telescope Science Institute): http://stsci.edu/top.html