I second The Reasoned Schemer as a fantastic introduction to logic programming. You can get miniKanren and its variants here - http://code.google.com/p/iucs-relational-research/. They'll run in pretty much any R5RS Scheme.
If you're a Clojurian you can give my bells & whistles implementation a spin: https://github.com/swannodette/logos. It has good performance, tabling, pattern-matching, and disequality constraints.
If you're a Clojurian you can give my bells & whistles implementation a spin: https://github.com/swannodette/logos. It has good performance, tabling, pattern-matching, and disequality constraints.