The press and everyone else are having fun with this one.
Last night I heard (from a regular commenter on this blog, no less) a fine analogy to what Benedict seems to have said on the moral level: When robbing a bank, just don't shoot the teller.
In other words, the sort of case that the Pope seems to raise is already cut off from openness to new life and is already a case of compounded disorder, injustice, and misery. In such a case, perhaps using a condom to (perhaps) prevent the transmission of HIV could mitigate the tragedy of the whole business and be the beginning of a journey to real morality.
The problem with contraception is that it attempts to divide the unitive and life-giving powers of sexuality. The rotten fruit of this separation--which has been more or less accomplished in our culture--is in evidence all around us. In the sad and sinful case in which the Pope is speaking, neither of these powers is present in the first place, so there is nothing to frustrate through the use of a condom.