Worth a reread:
Cardinal Ratzinger's (now Pope Benedict) sermon on moral relativism

"Every day new sects are born and we see realized what St. Paul says on the deception of men, on the cunning that tends to lead into error (cf. Ephesians 4:14). To have a clear faith, according to the creed of the Church, is often labeled as fundamentalism. While relativism, that is, allowing oneself to be carried about with every wind of "doctrine," seems to be the only attitude that is fashionable. A dictatorship of relativism is being constituted that recognizes nothing as absolute and which only leaves the "I" and its whims as the ultimate measure."

More here: http://www.zenit.org/english/visualizza.phtml?sid=69555