Here’s an article on the principles of lighting a game for game design. It’s very different from lighting things for illustrative/art purposes.

It talks about how simplified and concentrated lighting can be way more effective in leading the player than artistically lit environments, or lighting that ignores the fundamentals of game design (Condemned for example, breaks these rules to such utter frustration, that I found myself throwing the controller not because of player deaths, but because of running in circles unable to progress).

http://www.l4d.com/blog/post.php?id=2129