Space Science Links for Teachers and Students:

Cosmology and CMB:

An Introduction to the CMB - http://background.uchicago.edu/%7ewhu/beginners/introduction.html
A tutorial on the physics of the CMB by Wayne Hu of the University of Chicago.
Cosmology Tutorial - http://www.astro.ucla.edu/%7ewright/cosmolog.htm
A college level tutorial on cosmology by WMAP Science Team member Ned Wright of UCLA.
Cambridge Cosmology - http://www.damtp.cam.ac.uk/user/gr/public/cos_home.html
Brought to you by Cambridge University.
History of Cosmology - http://www.aip.org/history/exhibits/cosmology
A site by the Center for History of Physics, a Division of the American Institute of Physics.

General astronomy:

Astronomy Picture of the Day - http://antwrp.gsfc.nasa.gov/apod/astropix.html
Each day a different image or photograph of our universe is featured, along with a brief explanation written by a professional astronomer.
Ask the Space Scientist - http://image.gsfc.nasa.gov/poetry/ask/askmag.html
An interactive forum for your questions on astronomy and space science.

Educational sites of other NASA missions:

Chandra X-Ray Observatory - http://chandra.harvard.edu/edu/index.html
The NASA Great Observatory for studying the X-ray universe.
Hubble Space Telescope - http://hubblesite.org/
The NASA Great Observatory for studying the optical universe.
Spitzer Space Telescope (SIRTF Infrared Observatory) - http://www.spitzer.caltech.edu/
The NASA optical observatory for studying the infrared universe.
FUSE Education and Outreach - http://fuse.pha.jhu.edu/outreach/
The Far Ultraviolet Spectroscopic Explorer mission.
IMAGE POETRY - http://image.gsfc.nasa.gov/poetry/
IMAGE is a space science mission to study the Earth's magnetosphere.
Other NASA Missions - http://spacescience.nasa.gov/missions/index.htm
A complete linked list of past, present and future missions flown by the Office of Space Science at NASA Headquarters.
NASA Structure and Evolution of the Universe (SEU) Theme - http://universe.gsfc.nasa.gov/
The education pages sponsered by the SEU Theme Office at the Office of Space Science at NASA Headquarters, with a link to the Educators Forum.

Educational Resources:

Astronomy Education at the AAS - http://www.aas.org/education/
A portal to educational projects sponsored by the American Astronomical Society.
Astronomy Education at the ASP - http://www.aspsky.org/education.html
A portal to educational projects sponsored by the Astronomical Society of the Pacific.
CERES Project - http://btc.montana.edu/ceres/
An extensive collection of activities from Montana State University, many tied to NASA themes.
Google Earth- add on - http://earth.google.com/gallery/kml_entry.html#tMicrowave%20Sky
Download this small KML file and drag it into to Google Earth 4.2 or greater (Places menu) for a view of the Cosmic Microwave Sky.
Inside Einstein's Universe - http://cfa-www.harvard.edu/seuforum/einstein/resources_ed.htm
Great educational resources and ready made presentations on Cosmology- for teachers, scientists and informal educators.
NASA Quest - http://quest.arc.nasa.gov
Home of NASA's K-12 Internet Initiative.
NASA Quest- Online Educational Resources - http://questdb.arc.nasa.gov/lesson_search.htm
A guide to educational resources of all kinds.
NASA Educational Services - http://education.nasa.gov/home/index.html
Communicate with other teachers on the Web through this site.
Astronomy Education Resources - http://www.astro.washington.edu/projastro/
A K-12 Outreach Project at the University of Washington.
National Air and Space Museum - http://www.nasm.si.edu/
The name says it all.
Careers in Astronomy - http://www.aas.org/education/careers.html
An on-line pamphlet maintained by the American Astronomical Society.