Pascal Costanza's "Highly Opinionated Guide to Lisp" (seen on the info-mcl mailing list) is an excellent introduction to lisp that focuses on teaching newbies about the context and culture of lisp as opposed to the definitions of car and cdr. This is the sort of resource I find myself more interested in when I learn a language--a guide to important features from the perspective of someone who is new to the language.

Since Pascal is not neccessarily a lisp expert yet I won't be surprised if people find things in his introduction that could be improved, but it looks pretty solid to me.