Programmers resource, a number of old graphics programming related docsuments (1999)
Warp's CSG reference. Shows how the various CSG operations in POV-Ray work.
FuzzyPhoton - The Raytracing Repository
This site, written by Siddhartha Chaudhuri in 2002, tries to explain the basics of raytracing from a technical point of view.
Leveller Documentation - About Heightfields
A consice discussion on what height fields are and the technology behind their creation by Ray Gardener (2003)
The White Flame Page of Learning - Algorithms
Sick of hearing people name off algorithms that you should use, yet you have no clue what they are, much less how to implement them? Sick of people who won't take the time to explain algorithms and instead reference you to a book that you can't afford? Well, here's some info to help you out, for both the beginner and the advanced.
3D Cafe's Free Stuff
Tutorials covering many modelling programs plus a couple related to POV-Ray animations. Also contains large number of downloadable 3D models, but not in POV-Ray format and texture maps.
Anatomy of an Explosion
A discussion on modelling explosions using computer graphics animation techniques by Bradon Davis . (Not POV-Ray specific)
FRACTINT L-systems tutorial
An L-System tutorial by William McWorter that quickly covers the basics and a number of applications, such as for generating plants and tiled textures. (Not POV-Ray specific)
Imaging the Imagined : Modeling with Math & a Keyboard
The math, theory & practice of rendering, imaging, and animation. Has some excellent interactive demonstrations to browse through. By Paul Flavin 2002
A discussion on the use of LParser based systems by C.J.van der Mark. POV-Ray has been used to generate many of the illustrations used in the tutorial.
Modelling the Surface of the Human Cortex
Informally describes a project aimed at generating a computer based surface model of a human cortex. By Paul Bourke 1997. (Not POV-Ray specific)
Modelling Human Heads
General discussion on the computer generation of terrain using various techniques.
Terrain information Page Micro tutorial
A brief tutorial on aspects of creating terrain in computer graphics applications. Not POV-Ray specific.
The Recursive Ray Tracing Algorithm
An Excellent introduction to Raytracing
Using 2D in a 3D World
An interesting discussion on when to use 2D objects in your 3D scenes. The topic is not program specific so will apply to any 3D work that you may do.