Math
Math Drills
Math Drills is the web site recommended by the teachers at school. It is a great resources for worksheets that can be printed out.
Math Facts Cafe
Math Facts Cafe can be a little confusing to set up, but select the "Flash Cards" button and then the appropriate grade. These drills have the benefit of giving the student instant feedback if the answer is correct, or not.
Wild On Math
Wild on Math is a good, simple site that very quickly allows the student to select the math facts they would like to work on and at what level. It then sets up a 20 question, timed environment that grades the student upon completion. A good way to work on memorization.