For more info on the Leuchter Report watch Errol Morris' Docu Mr Death
Mr. Death: The Rise and Fall of Fred A. Leuchter, Jr. http://www.imdb.com/title/tt0192335/
This movie includes the actual footage of Leuchter's illegal chiseling bits off the gas chamber wall while Ernst Zundel's film crew stood guard on the outside of the gas chambers, along with interviews of Zundel and Irving themselves. Also prominently appearing in this documentary is Prof. Robert Jan Van Pelt who completely debunks Irving's aspersions based on hard evidence from the site itself and documents from the Auschwitz archives. I found this film to be a compelling complement to Denial and highly recommend it despite the highly unsavory personality of the film's protagonist.