Where can I find info on Planar, Cubic, Spherical projections?

Hi, I wanted to learn how to project textures on surfaces (planar/cubic/spherical). This is a feature that can be seen on most of 3D modelling/animation program (Lightwave, Maya, 3DSMAX). Where can I more info? I want to learn the math behind, and maybe get some opengl code. Thx in advance!
Regards, Joy F.