The first tutorial is from Itchy Animation. A very detailed tutorial covering a span of 40+ pages. Originally ment to be a 7 part series. Now it seems he is working on publishing the article into book form. We'll keep an eye out for it, thats for sure. As it is its a great read. The articles start at the basics of lighting and what is happening. It progresses to where light comes from in certain situations and what affects the light (ie. clouds outside). The last page covers artificial lighting.
The second tutorial is from Warped Space. Using references from David Maas you know right away that its going to have some great examples to work with. I really liked how the article at Warped Space really talked about the emotional contribution that lighting can make to a scene.
The author says the following about the article:
The goals of lighting in 3D computer graphics are more or less the same as those of real world lighting. Lighting serves a basic function of bringing out, or pushing back the shapes of objects visible from the camera's view. It gives a two-dimensional image on the monitor an illusion of the third dimension-depth. But it does not just stop there. It gives an image its personality, its character. A scene lit in different ways can give a feeling of happiness, of sorrow, of fear etc., and it can do so in dramatic or subtle ways. Along with personality and character, lighting fills a scene with emotion that is directly transmitted to the viewer.
Trying to simulate a real environment in an artificial one can be a daunting task. But even if you make your 3D rendering look absolutely photo-realistic, it doesn't guarantee that the image carries enough emotion to elicit a "wow" from the people viewing it. Making 3D renderings photo-realistic can be hard. Putting deep emotions in them can be even harder. However, if you plan out your lighting strategy for the mood and emotion that you want your rendering to express, you make the process easier for yourself.
The overall thrust of this writing is to produce photo-realistic images by applying good lighting techniques. I will use Lightwave 3D to demonstrate the lighting techniques used, but these techniques can be applied in any 3D software.