Yahooligans Math with several other links http://yahooligans.yahoo.com/School_Bell/Math/
Ask Dr. Math Students may submit question or check out other posted questions http://mathforum.org/dr.math/
Math Dictionary for Kids Will help students define math vocabulary terms http://www.teachers.ash.org.au/jeather/maths/dictionary.html
Algebra Help solves problems step by step http://algebrahelp.com/
Study Works! Online Has links for students as well as parents http://www.studyworksonline.com/
Brain teasers http://www.eduplace.com/math/brain/index.html
Pre-Algebra problem of the week http://mathforum.org/prealgpow/