When I was in math I had the most difficult time learning my times tables. I found that flash cards helped me the most. Using repetition in learning math seemed to be the answer. Of course, when I learned math, there was no such thing as learning on the computer. However, now we have great programs for learning online.
Learning Games for Kids has a whole page of online flash cards for learning your math skills. There are flash cards for addition, subtraction, multiplication, and division. So no matter what area you need practice in, they can provide some support. Remember that repetition is the best remedy when it comes to math. So keep practicing!