Google Web Directory – Science: Math
http://directory.google.com/Top/Science/Math/
Google's science links.

MathDL
http://www.mathdl.org/
MathDL is an online resource published by the Mathematical Association of America. The site provides online resources for both teachers and students of mathematics.

Wolfram Web Resources
http://www.wolfram.com/webresources.html
Wolfram Research pioneered the modern conception of technical computing when it launched Mathematica 15 years ago. Now millions of users on every continent use Mathematica technology to advance science, engineering, math, finance and many fields besides.

Eisenhower National Clearinghouse Digital Libraries
http://www.encdl.org/
This portal provides users with the ability to search individual ENC collections or across multiple ENC collections. Right now five collections can be searched - ENC Online, FEDRL, ICON, GSDL, and the Learning Matrix. Each of these collections has a specific audience although all collections deal with the topics of science, mathematics, and technology. The description found on the homepage for each collection should give you some insight into which collection or collections would best suit your needs. All resources have been cataloged using the IEEE Learning Object Metadata (IEEE LOM) standard metadata schema.

FEDRL
http://www.encdl.org/search/simple/0,5046,,00.shtm
Federal Education Digital Resources Library (FEDRL) features a collection of high-quality science and mathematics digital resources for the K-12 education community. Here you will find descriptions of a range of online materials that were developed with U.S. Department of Education or National Science Foundation funding. These materials include applets, lesson plans, animations, magazine articles, and more.

Kathy Schrock's Guide for Educators - Mathematics Resources
http://school.discovery.com/schrockguide/math.html
A categorized, annotated list of mathematics sites to help educators, teachers, and parents enhance instruction and support the curriculum.

The Math Forum
http://mathforum.org/
A comprehensive and frequently updated listing of math lessons available on the Internet, along with grade level listings of math resources. Includes the popular "Ask Dr. Math" Project, which answers math questions from kindergarten to college. The Math Forum helps students learn mathematics through the use of the Internet and innovative technologies. It also gives advanced students an opportunity to pursue their interests as well as use their skills to help others.

ESTME Week : Web Site Gallery
http://www.estme.org/gallery/index.html
This gallery features award-winning sites that provide a myriad of possibilities for enriching science, technology, and/or mathematics education. Culled from a variety of distinguished institutions, organizations, and individuals, this list is by no means exhaustive. It does, however, provide an excellent sampling of the vast amount of information on the Web. Many of these sites also provide links to other useful resources.

iLumina
http://www.ilumina-dlib.org/
iLumina is a digital library of sharable undergraduate teaching materials for chemistry, biology, physics, mathematics, and computer science.

RDN Virtual Training Suite
http://www.vts.rdn.ac.uk/
RDN Virtual Training Suite - a set of free online tutorials designed to help students, lecturers and researchers improve their Internet information literacy and IT skills.

PlanetMath
http://planetmath.org/
PlanetMath is a virtual community which aims to help make mathematical knowledge more accessible. PlanetMath's content is created collaboratively: the main feature is the mathematics encyclopedia with entries written and reviewed by members.

TeachEngineering.com
http://www.teachengineering.com/
This teacher resource, TeachEngineering.com, helps teachers enhance learning, excite students and stimulate interest in science and math through the use of hands-on engineering.

KMODDL
http://kmoddl.library.cornell.edu/
KMODDL is a collection of mechanical models and related resources for teaching the principles of kinematics--the geometry of pure motion.

MERLOT - Mathematics and Statistics
http://www.merlot.org/artifact/BrowseArtifacts.po?catcode=223&browsecat=223&sort=rating
MERLOT is a free and open resource designed primarily for faculty and students of higher education. Links to online learning materials are collected here along with annotations such as peer reviews and assignments.

Science-Web-Award: Mathematics
http://www.science-web-award.com/math.htm
Given the award "For Extraordinary Effort".

Galaxy: Mathematics
http://www.galaxy.com/galaxy/Science/Mathematics/
Galaxy is the original searchable Internet directory. Our mission is to provide contextually relevant information by integrating state-of-the-art technology with the human touch.

Yahoo! Science: Mathematics
http://dir.yahoo.com/science/mathematics/
Yahoo! Search directory.

About.com's: Mathematics
http://search.about.com/fullsearch.htm?terms=Mathematics
A listing of About.com's science resources.