See also the Google Saffron search engine linked to in my signature. A search on the Kalama Sutta will yield several interesting results. Be aware though there are some terrible misrepresentations of the Kalama Sutta out there, so be careful with any that take liberties to re-write it according to their own agenda. The one Ben links to is fine.
Through corruption of the Dhamma comes corruption of the discipline, and from corruption of the discipline comes corruption of the Dhamma. This is the first future danger as yet unarisen that will arise in the future. You should recognize it and make an effort to prevent it. (AN 5.79)
Neither traceable in the Discourses nor verifiable by the Discipline, one must conclude thus: 'Certainly, this is not the Blessed One's utterance; this has been misunderstood by that bhikkhu — or by that community, or by those elders, or by that elder.' In that way, bhikkhus, you should reject it. (DN 16)