Online Free Tutorials and Books

• Learning Modern 3D Graphics Programming is probably the most extensive free, well maintained online/offline (download-able for desktop, tablet and even kindle) book on modern OpenGL programming (i.e. it doesn't use fixed-function pipeline at all). The author is such a helpful chap, when you raise a question in StackOverflow on OpenGL, he'd probably be the first to answer it, clearly and lucidly.
• OpenGL-Tutorial is also modern and good, but isn't that extensive/detailed as compared to the former; although perspective projections are explained with diagrams extremely well here.
• OGLdev has close to 40 tutorials on modern OpenGL with nice explanations and rendered outputs.
• Open.GL has begun posting modern OpenGL tutorials which seems to be good too.
• Lighthouse 3D has tutorials for most of computer graphics: math, Open GL, GLSL, GLUT, writing your own light weight library for game development.
• An Intro to Modern OpenGL is short and sweet; it's good to understand the rendering pipeline more clearly; once again because it's very illustrative. For more in-depth understanding, read A trip through the Graphics Pipeline.
• OpenGL on WikiBooks has a lot of hands-on tutorials which seem to be good too.
• Song Ho Ahn's Articles/Tutorials on CG Math and OpenGL were also useful.
• Matrix and Quaternion FAQ should conquer your doubts on vectors, matrices and quaternions.
• Linear Algebra Free Text by Professor Jim Hefferon covers linear algebra from ground up with lot of exercises.