The Zombie Survival Guide, World War Z, and Zombie Survival Guide:Recorded Attacks all are fun reads. Max Brooks (son of Mel Brooks) is a wonderful writer, and he presents an interesting take on the subject.
BTW: World War Z is currently being made into a movie (yay!) produced by Brad Pitt's production company and starring...Brad Pitt (boo!) for a scheduled release next summer. Sadly, Max Brooks is not writing the screenplay but the director is Marc Forster (James Bond "Quantum of Solace") so I still have hope that it might be good. Apparently, it is already the most expensive Zombie movie in Hollywood history - but I'm not sure what that really means since most of the Zombie movies I've seen looked like they cost less than $100 to produce! Guess I'll just have to wait and see, and I am looking forward to seeing it regardless of what they end up with.