Over 800 Free Maths Videos
Khan Academy is a not-for-profit organisation set up to promote quality free education for everyone worldwide. The videos produced by them are clear, lengthy, and well detailed. Subjects include algebra, trigonometry, finance, statistics, and probability. Other subjects such as physics and chemistry are also explored.
To see the videos that are grouped together on their youtube channel, head over to:
http://www.youtube.com/user/khanacademy