These are some sites that have Math resources and helps.

General

National Council of Teachers in Mathematics (NCTM)

NCTM Illuminations. Resources and lessons.

SVSU Regional Math and Science Center (MASER Mathematics). Great Site!

Math Forum @ Drexel. All types of resources including lessons and a searchable library of topics.

Education World ® - Lesson Planning Math Sites to Count On!. Math site resources by grade level.

allmath.com - math site for kids! Home of flashcards, math biographies and Ask The Experts. Fun!

Games

CanTeach Math Games

Fun Mathematics Lessons by Cynthia Lanius. Games.

Measure 4 Measure Sites That Do the Work For You. Very Cool!

Math is Fun. Many activities for all ages.

Specific

A Math Website. Wayne County RESA's Middle School site.

Cynthia Lanius' Lessons Geometry Online

Math Forum - Geometry Problem of the Week