Math dot com is a wonderful resource for math students. From basic skills to trig! This is a great place to get help for those students who need a little extra information.
http://www.math.com/

The Math Forum is a site with great information for the teacher and student.
http://www.mathforum.org/

Zona Land is a special website for kids who love science and math. Take a look around and find some puzzles to play with.
http://id.mind.net/~zona/

Math goodies is a free math educational website with interactive lessons and more!
http://www.mathgoodies.com/

Cool Math dot com is a very fun and exciting place for "kids 13-100" It features interactive games and other really cool stuff to challenge your brain!
http://www.coolmath.com/