The Khan Academy
Has videos on all of the following topics: Calculus, Pre-calculus, Trigonometry, Algebra, Pre-Algebra, Linear Algebra, Arithmetic, Geometry, Differential Equations, Probability, Singapore Math, California Standards Test: Algebra, California Standards Test: Geometry Banking and Money, Credit Crisis, Finance, Physics, California Algebra II, MAT Preparation, SAT Preparation, 2009 Mental Boot Camp.