There's a list of introductory AI texts in the bibliography section
of the FAQ [4-0].  Also, check out the web links in section [5-2].

  [1-3a] I'm writing a game that needs AI.
  
  It depends what the game does.  If it's a two-player board game,
  look into the "Mini-max" search algorithm for games (see [4-1]).  In
  most commercial games, the AI is is a combination of high-level
  scripts and low-level efficiently-coded, real-time, rule-based
  systems.  Often,  commercial games tend to use finite state machines
  for computer players.  Recently, discrete Markov models have been used
  to simulate unpredictible human players (the buzzword compliant name
  being "fuzzy" finite state machines).