An entire online text for Precalc from the Univeristy of Houston.

[Brilliant!]

http://online.math.uh.edu/Math1330/index.html

It's the best free source I've seen. It's the project of grad students and is a comprehensive online text that has everything you'd expect from a textbook. And on top of that, there are streaming lectures.

[qntty]

University of Washington (http://www.math.washington.edu/~m120/) has a free precalc book too.

[gabrielh]

Excellent books. These should help me greatly.

[huenikad]

These look great and should help a lot.

[A.O'Neill]

Thanks, I've been looking for something like this for some time. Attempting to catch up with the education I should have received in high school...

[spartacus82]

Is there any trigonometry materials that anyone knows out there that I can consume within 3-5 hours max? I need it for a project and it has been a long time since my high school days... I need a quick refresher....

[Sankaku]

Very short Trig course:

http://www.clarku.edu/~djoyce/trig/

[spartacus82]

Thank you very much Sankuku... It is very much appreciated!

[dextor]

Thanks 'Brilliant!', very useful precalculus textbook.

[fan_103]

Thanks!