An interactive math site where kids can practice basic facts http://www.mathfactcafe.com/
Math review material from Algebra to Differential Equations! A really great site! http://www.sosmath.com/
Internet 4 Classrooms--Elementary Math Links http://www.internet4classrooms.com/math_elem.htm
Internet 4 Classrooms--Secondary Math Links http://www.internet4classrooms.com/math_sec.htm
Math links and more on Mr. Parker's site. http://www.teacherweb.com/pa/northwesternelementary/parker/links1.stm
A free download for OSX users -- practice basic math facts -- timed test -- provides feedback http://mac.softpedia.com/get/Educational/Ryans-Math-Quiz.shtml
Check out this link to Mr. Clapper's page. He has links to a lot of math & science resources, and more. http://www.teacherweb.com/pa/northwesternelementary/mrclapper/