Khan Academy is a free on-line program for students that features math how-to videos. This allows students to review concepts they are struggling with or to advance to new concepts as they are ready.
60 Minutes did a feature on Khan Academy. Go to http://http://www.cbsnews.com/8301-18560_162-57394905/khan-academy-the-future-of-education/?tag=mncol;lst;4
To register, you need a Gmail or Facebook account. Go to http://www.khanacademy.org