Xtra Math
This site is similar to Fasttmath previously used in school. Once an account is created, your child can practice basic facts.
http://xtramath.org
Multiplication.com
This site offers games and resources for teaching and learning multiplication facts.
http://www.multiplication.com/
Practice a variety of 3rd grade math topics. Video tutorials are clean and clear, focusing on the math and not the presenter. The website is heavy on text and not as child oriented as others, and thus may require parent support to begin navigating. The content is targeted to each grade, so I have linked to grade 3.
Greg Tang Math
This site offers fantastic activities to promote problem solving. It is also an opportunity to explore his wonderful books about math.
http://gregtangmath.com/Home/index
Bedtime Math
This program emails a daily math problem with 3 levels of questions: wee ones, little ones, and big ones. The questions all refer to the same story and get progressively more challenging.
Typing Club
http://house-bowman.typingclub.com