I believe someone posted a link to this website on the LivingMath! yahoo group a while back. I took a look at Khan Academy and was amazed at all of the math help available there.
Salman Khan, the founder of the website, has made YouTube videos for many math topics, from basic addition to calculus. These are basic chalk on blackboard style lectures, but the concepts are clearly explained and follow ordered lessons that are labeled by topic.
These videos would make a great supplement to a math program and might help students understand concepts they are struggling with. You might be able to use these as a basis for a custom-tailored math program along with other resources and practice problems. However, I am not a math expert. If anyone uses the videos this way, I would be interested to know how it works for you.
There are also SAT Prep videos that offer explanations of the problems in the practice tests of "The Official SAT Study Guide!" You will need the book. The Khan Academy SAT Prep page gives suggestions for using the book and videos.