You might want to check out the "AI Game Programming Wisdom" series. I think at this point, there are four of them. "Game Programming Gems" is another series

You might want to check out the "AI Game Programming Wisdom" series. I think at this point, there are four of them. "Game Programming Gems" is another series worth checking out (I think there are 8 at this point); each book normally has a section on game AI. The books are a series of articles written by industry practitioners solving a problem they have run across. Normally the articles contain inline code, and the books come with a CD with executable examples and code to accompany the articles.