The theological commision he authorized in 2004, chaired by the present pope, certainly did express official Church teaching when it declared no intrinsic conflict between the Catholic Faith and Darwinism.
In a word, (or two), bu!!$#it. The Catholic Church's only official stance on Darwinism is that Catholics are allowed to study it. After that it's the liars, socialists and atheists out there who take it further than that. Pius XII in fact said that he believes, (and hopes), evolution will soon be lost in the dust of history.
Pope JPII never said ANYTHING officially, (as in an Encyclical). He spoke once publicly on the subject as a PRIVATE DOCTOR, and he (allegedly) stated that "evoution is more than just a theory". Many Catholic scholars believe the original statemnent was "evoultion has more than one theory", but after it was translated into English and twisted in the media it came out as the former. In any case, it was spoken in a speech to scientists, and was not officially or doctrinally declared to the Church faithful.