The following is a list of sites that are useful, fun and informative.
Illinois Council of Techers of Mathematics at www.ictm.org
National Council of Teachers of Mathematics at www.nctm.org
Mu Alpha Theta at www.mualphatheta.org. Great place for puzzles, games and challenging problems.
Ask Dr. Math at www.mathforum.org/dr.math/. A site that will allow a student to ask questions and receive help
www.kutasoftware.com Free practice worksheets for algebra and geometry
www.khanacademy.org Free video lessons on specific topics for all of math and many other disciplines.
There are many more useful sites which assist students in mathematics. Search and find your favorite.