These are links provided for teachers of mathematics.  The usual link to National Council of Teachers of Mathematics and the website Illuminations from which you can get lessons from are first.  I will add descriptors as I get a chance to and I want to leave the addresses in case you want to copy this page. 

Math Help for All Grades:  A comprehensive resource and guide for all math related issues.
http://math-and-reading-help-for-kids.org/article_directory/Math.html
 

Prentice-Hall Interactive Programs including Internet Activities:  http://www.phschool.com/atschool/Mathematics/Geometry/Teacher_Area/GEO_T_BK_index.html

Interactive Math Applet:  Geometry--Transversals/Parallel Lines/Name that angle: http://www.shodor.org/interactivate/activities/angles/index.html

Glencoe Math Resources:  Pre-Calc http://www.glencoe.com/sec/math/precalculus/amc_04/index.php/nm

Glencoe Math Resources:  Geometry http://www.glencoe.com/sec/math/geometry/geo/geo_04/index.php/nm

Glencoe Math Resources:  Algebra 2 http://www.glencoe.com/sec/math/algebra/algebra2/algebra2_03/index.php4/nm

Glencoe Math Resources: Algebra 1 http://www.glencoe.com/sec/math/algebra/algebra1/algebra1_03/index.php4/nm

Glencoe Math Resources:  Pre-Algebra  http://www.glencoe.com/sec/math/prealg/prealg03/index.php4/nm

Neufeld Math-- http://www.neufeldmath.com/

http://www.nctm.org/

http://illuminations.nctm.org/

http://www.explorelearning.com/

Math Glossary:  http://www.harcourtschool.com/glossary/math2/index_temp.html

Dave’s Math Tables:  http://www.math2.org/index.html

Ask Dr. Math:  http://mathforum.org/dr.math/

http://sosmath.com/

http://www.gomath.com/

Geometry:  http://library.thinkquest.org/2647/geometry/geometry.htm

Pre-Algebra:  http://library.thinkquest.org/20991/prealg/frac.html

Geometry:  http://library.thinkquest.org/20991/geo/index.html?tqskip1=1&tqtime=0628

http://www.mathleague.com/help/help.htm

http://www.webmath.com/

World Wide Web Math Tutor—Fractions/Decimals only:  http://library.thinkquest.org/2949/

http://hotmath.org/index_hm.html

Geometry:  http://www.dummies.com/WileyCDA/DummiesArticle/id-1194.html

http://mathcounts.org/

http://www.pacificnet.net/~mandel/Math.html

http://www.sitesforteachers.com/resources_sharp/math/math.html

Tips for new Math teachers:  http://www.mathgoodies.com/articles/beginner_tips.shtm

Ten Commandments for Math Teachers:  http://www.mathpower.com/tencomm.htm

http://www.bonita.k12.ca.us/schools/ramona/teachers/carlton/tutorials.html

http://mathstar.nmsu.edu/teacher/lessons.htm

Links for Math Teachers:  http://www.fcasd.edu/schools/dms/tm.htm

http://webs.wichita.edu/facsme/resourc.htm

Math Links for Teachers:  http://www.kent.k12.wa.us/curriculum/math/teachers.html

http://mathcentral.uregina.ca/

http://www.geometry.net/math_help_desk/math_teachers.html

http://www.edhelper.com/

http://home.amaonline.com/teacherstuff/mathteacher.htm

http://teams.lacoe.edu/documentation/places/math/teacher.html

http://www.austintown.k12.oh.us/~aust_tr/teachers.htm

http://db.education-world.com/perl/browse?cat_id=2828

http://www.sd68.k12.il.us/schools/HIGHLAND/resource/mathint.htm

http://archives.math.utk.edu/k12.html

http://www.allmath.com/

Math Educators:

http://www.pbs.org/teachersource/whats_new/math/archives.shtm#g

http://mathforum.org/

http://www.maa.org/welcome.html

http://www.ma.utexas.edu/users/mks/teachers/resources.html

http://education.ti.com/educationportal/

IMP Program-- http://www.mathimp.org/general_info/iis/index.html

Creativity in Math:  http://www.cut-the-knot.org/ctk/index.shtml