Experts Exchange  
   Ask questions about all things related to computers. You must register/login before you can participate at this site.
   http://www.experts-exchange.com/

Ask A Scientist  
   You can ask a scientist a question on the WWW MadSciNet: The 24-hour exploding laboratory.
   http://madsci.wustl.edu/

Ask a Marine Science Expert  
   Email your question after checking the archive of previous questions and answers.
   http://whale.wheelock.edu/whalenet-stuff/ASK_SCI.html

Ask A Scientist About Liquid Crystals  
   A starting point for students and teachers interested in liquid crystals and the science and mathematics from which they arise: physics, chemistry, mathematics, computer science, polymer science, display engineering and information management.
   http://olbers.kent.edu/alcomed/Ask/ask.html

Ask a Volcanologist  
   All things volcano related, plus archives of previous questions.
   http://volcano.und.nodak.edu/vwdocs/ask_a.html

Ask an Earth Scientist  
   Experts at the U of Hawaii answer questions about volcanoes and igneous rocks, earthquakes and seismology, natural disasters, geochemistry, the environment, pollution, hydrology and water quality, minerals, gems and crystals, geophysics, sediments and sed
   http://www.soest.hawaii.edu/GG/ASK/askanerd.html

Ask The Space Scientist  
   Ask a question and check out the extensive archives for the many questions asked at this site.
   http://image.gsfc.nasa.gov/poetry/ask/askmag.html

Ask Dr. Universe  
   Dr. Universe has a whole university full of experts ready to tackle your question on any subject. Explore the question of the day, and longer featured answers.
   http://www.wsu.edu/DrUniverse/

Ask Bob Treat  
   Answers to questions in the natural, social and computer sciences from Bob Treat. Post your question and you'll usually get a response within 24 hours.
   http://www.uwm.edu/cgi-bin/bobtreat/messageboard/view.pl

ScienceNet  
   A free science information service, staffed by scientists who are expert in explaining complex topics in everyday language. Search the online database of previously answered questions. If you can't find an answer then send your question via e-mail.
   http://www.sciencenet.org.uk/

Ask Mr. Water Wizard  
   Do you have questions about water? Questions about water quality in some nearby stream or lake? About drinking water? About water quality testing? About aquatic life such as fish, turtles, snakes, and insects, in your local waterways? Mr. Water Wizard can
   http://www.sra.dst.tx.us/srwmp/mr_water_wizard/default.asp

Physlink - Ask Experts Physics and Astronomy Questions  
   Ask questions and check out the archives, organized by topic.
   http://www.physlink.com/Education/AskExperts/Index.cfm

Curious about Astronomy? Ask an Astronomer!  
   Browse archives of previous questions and answers, or submit a question to be answered by astronomers at Cornell University.
   http://curious.astro.cornell.edu

Science Questions & Answers  
   Expert responses to questions on biology, chemistry, geology, and other branches of science.
   http://www.sciam.com/askexpert_directory.cfm

NEWTON Bulletin Board System  
   Ask-a-scientist service designed for K-12 teachers and their students - operated by the Argonne Nat'l. Laboratory, Div. of Educational Programs.
   http://www.newton.dep.anl.gov

Ask Dr. Global Change  
   He stands ready to answer your most difficult questions about global change on planet Earth. Archives are available.
   http://gcrio.custhelp.com/cgi-bin/gcrio.cfg/php/enduser/home.php

Ask a Rocket Scientist  
   Explains design, technology, aerodynamics, history, space travel, and other topics related to aerospace engineering.
   http://www.aerospaceweb.org/question/

Ask An Aviculture Expert  
   Birds and bird care questions. Not a substitute for a trip to the vet.
   http://www.upatsix.com/ask-experts/

How Things Work  
   Ask about almost anything related to the physical world, and check the well-organized archives for answers to previous interesting questions.
   http://howthingswork.virginia.edu/

Ask Shamu  
   Ask and read archives of questions and answers. Mainly about marine biology and the environment.
   http://www.seaworld.org/ask-shamu/faq.htm

Ask A Geologist  
   Do you have a question about volcanoes, earthquakes, mountains, rocks, maps, ground water, lakes, or rivers? A service of the earth scientists at USGS.
   http://walrus.wr.usgs.gov/ask-a-geologist/