To give help for kids with the SAT's and similar tests, Barnes & Noble provides popular study guides called SparkNotes. They range from all kinds of subjects from history to math and science. Some think it's a cheating way to study but I feel that if your kids learn and they pass then it's not cheating. There is nothing wrong in opinion to having everything you need at your fingertips.
I feel that a lot of time can be wasted if a person has to do tons of research online to help them study. Using a study guide is a perfect way to study while managing time. A student still has to read, comprehend, and develop their memory. And I recommend that you also get your kids a good dictionary as well so that they can look up words that they are not familiar with from the SparkNotes study guides.
I'm not in school anymore and I haven't been for a long time, but it would have been great to have one of these study guides for reading the Scarlet Letter, for example. I may have gotten a better grade if I had! (Maybe!)