The Khan Academy, essentially a cyberspace school, offers all students free(!) instruction in a variety of subjects ranging from math to lab science to history. Salman Khan started making YouTube videos a few years ago-- originally to help his cousins, but then as part of a larger educational project that has taken much of the country by storm.
If you're looking for Khan's SAT prep videos, click here. If you have the College Board's official guide to the SAT I, you can follow along with Khan on his videos.