WWW Virtual Library History of Science, Technology & Medicine
Though it's no longer being maintained, this site -- begun in 1994, out of the University of Melbourne in Austrailia -- is still very useful for general references in the history of science (arranged in alphabetical order) and specialized subject areas (astronomy, genetics, physics, etc.).
Pat Huckle's Gender and Science Links
This comprehensive links library was put together by Pat Huckle at San Diego State University, for her 1998 class on "Science and Technology in Women's Lives." It includes a link to the "Gender, Science, and Techology Gateway," an excellent research tool.
Bibliography of Gender and Science References
This site is produced by PROMISE (Projects for Multicultural and Interdisciplinary Study and Education).
Archives of Women in Science and Engineering
The Iowa State University Library inaugurated its Archives of Women in Science and Engineering in April 1994. This new archive was born from the need to document the history of women in science and engineering -- (thoughtfully) including their social history as well as the story of their scientific achievements.
Four Thousand Years (!) of Women in Science
Philosophically, this is a somewhat schizophrenic site. On the one hand, the site creators emphasize (in their introduction) that in order to find women in the history of science "we must widen the definition of science as we look back in time" and understand that "what counted as success [in science] varied from century to century;" on the other hand, they conclude optimistically that "the results of science have no gender" and ultimately "solutions to problems come from research, thought and technology." Still, it holds a wealth of useful biographical and reference information, and includes an on-line photographic archive.
Women and Minorities in Science and Engineering
Simply the most comprehensive reference source on the subject. This site is especially useful for educational and social policy documentation -- e.g. various National Science Foundation and international surveys -- and for bibliographic research -- e.g. you can find the Library of Congress' bibliography on African-American women in the sciences here.
References -- History of Women in Science & Technology
Part of the Ada Project (see below), this is a good reference bibiography of works on women in science and technology. The disadvantage of this site is it's arranged in alphabetical order by author and it's not searchable -- so unless you're looking for a particular author, you'll have to resort to good old fashioned sight scanning to see if there's anything useful for your conference work..
Distinguished Women of Past and Present
This site has biographies of women who contributed to our culture in many different ways, and includes many women scientists.
Includes a list of all Nobel Laureates with links to biographical information, and the facility for visitors to add additional links.
Notable Women of Computing and Mathematics
The Ada Project: Women in Computing
Contributions of 20th-Century Women to Physics
Women in Developmental Biology (conceived by Evelyn Fox Keller)
Women of Science at the Woods Hole Marine Biological Laboratory