Basic math

"Essential Mathematics for Games and Interactive Applications" is good, but covers a disproportionate amount of 3D stuff; most of it has application in 2D as well but it might not be obvious to you.

"The Geometry Toolbox" is also really good.

(These are both books, you can find them on Amazon).

I need something free, I can't afford to buy a book right now, or I'd go look at a book store before I bothered you guys... although you didn't know that I didn't.

http://www.gamedev.net/reference/programming/features/vecmatprimer/
introduction on vectors.

http://www.euclideanspace.com/
It's more like a reference than a book that will teach you linear algebra and trigonometry.

http://www.d6.com/users/checker/dynamics.htm
Tutorials on basic rigid body dynamics

http://www.gaffer.org/game-physics/
Stuff by Gaffer. Basic introduction to physics, bit like Chris Hecker stuff, with more advance stuff that complements nicely.

See if you can make sense of those :)

Thanks, I'll check those out.

Many useful resources are at
Wolfram Mathworld