I came across this a month or so ago. It deals with metaphor in an interesting way. Instead of relegating it to being a mere linguistic twist it explores how metaphor underlies the very way we understand the world around us.
I found my first reference to it on c2 while poking around for AI texts. It isn't an AI text itself, but the information is insightful and likely applicable. I came across a few chapters online as well as a review on Peter Norvig's home site, which convinced me to pick it up from my local library.
http://www.c2.com/cgi/wiki?MetaphorsWeLiveBy
http://theliterarylink.com/metaphors.html
http://norvig.com/mwlb.html