An Introduction to Projective Geometry (for Computer Vision): A monograph aiming to provide a readable introduction to the field of projective geometry and a handy reference for some of the more important equations. HTML, PS or PDF versions.
Important Concepts from Projective Geometry: Webtext by Paul Beardsley.
Lecture Notes on Projective Geometry: By Balázs Csikós. Budapest Semesters in Mathematics. In DVI format.
Linear Systems of Conics: Graphics and formulae for systems of curves defined by linear combinations of quadratic equations.
MathWorld: Index to articles on Projective Geometry.
Projective Geometry: Rudolf Steiner's approach.
Projective Geometry for Multiple View Analysis: A new framework for studying the problems of camera calibration, motion determination, and 3D structure reconstruction in the most general case of totally uncalibrated views.
Projective Geometry Resources: Part of the Math Forum.
Wilson Stothers' Cabri and Conics Pages: A site devoted to (mainly projective geometry) illustrated by Cabri II and CabriJava.