The transcript of this speech can be found on the Vatican Website at: Meeting with the representatives of science at the University of Regensburg
The speech the Pope made, the source of current controversy, was delivered at a university and was about Faith and Reason. The Pope describes his time teaching at the university and their tradition of the faculty meeting as a group before the students in order to discuss how the different departments fit together to form a whole of knowledge.
The Pope speaks about the relationship between faith and reason. He states that he was recently reminded of this subject while reading a 1391 dialogue between Byzantine emperor Manuel II Paleologus and a Persian educated in Islam and Christianity. The quote the Pope specifically mentions is:
"Show me just what Mohammed brought that was new, and there you will find things only evil and inhuman, such as his command to spread by the sword the faith he preached".
He goes on to explain that violent conversion is contrary to Christian/Greek Philosophical notion of reason, and therefore is against the nature of God. The Pope continues with: " But for Muslim teaching, God is absolutely transcendent. His will is not bound up with any of our categories, even that of rationality. Here Khoury quotes a work of the noted French Islamist R. Arnaldez, who points out that Ibn Hazn went so far as to state that God is not bound even by his own word, and that nothing would oblige him to reveal the truth to us. Were it God's will, we would even have to practise idolatry." In these statements it appears (to me, at least) that the Pope is declaring that Christianity is based on reason and Islam is not.
The Pope uses the rest of the speech to describe the evolution of Christian philosophy, from its fusion with the reason of Greek philosophy, through its various stages of dehellenization, up through the present conflicts/potential partnership with modern science.
Nowhere in the speech does the Pope contradict the insinuation that Islam is evil and without reason. (Some may argue that all religion is without reason. Please, see the transcript linked above if you are interested in the Pope's treatment of this subject.)