Websites for SAT prep
MathTV is a tutorial site that covers math from the basics to calculus; good videos and demonstrations on whiteboard for clarification; there are also online books on the topics
MajorTests is a test prep site for not only the SAT but also the GRE and GMAT plus word lists; explanations are provided for wrong answers
Purple Math contains more tutorials for the math portion of the SAT
VocabTest is just that–review of many, many vocabulary words
Math.com is another site with general math reviews; well done, but contains lots of ads