Suite 101: Oil Painting 
From stretching canvas, to mixing oil colour, to discussions. Archive of articles.
http://www.suite101.com/welcome.cfm/oil_paintingNaturePainter Digital Canvas
Software to learn and practice oil painting right on your computer. Trial version available.
http://www.naturepainter.net/
Karen Patton Studios
Karen Patton sells a series of instructional videos, and also gives workshops in various parts of the United States. Also does commissioned portraits.
http://www.portraits4you.com/
Painting for Pleasure with Tony Carchia
Painting information packets and instructional videos.
http://www.painting-for-pleasure.com/
Bruce Kaminski: Painting Technique
Step by step demonstration of pure oil color and an egg oil emulsion. Combines the vibrant color of oil paint with the intensity and durability of tempera.
http://www.brucekaminski.com/process/
Oil Painting Techniques
In theory and practice, from aesthetics to selling completed works. An organized collection of notes covering many aspects of this medium.
http://www.oil-painting-techniques.com/
Oil Painting for Beginners by Andrew Whyte
Provides an introductory page from his course notes and a question and answer service.
http://www.andrewwhyte.com/painting/tutorials.htm
