Hmm, well.
There’s a lot of stuff on postmodern theology, but I think most of it is written as a reinterpretation of religion through a postmodern lens, or alternatively, a religious perspective of postmodernism.
It seems harder to find a skeptical analysis of the way that postmodern philosophy has affected religions and people’s propensity to have faith.
The closest thing I’ve been able to find is this:
Augustine and Postmodern Thought: A New Alliance against Modernity? (Bibliotheca Ephemeridum Theologicarum Lovaniensium)
http://www.amazon.com/Augustine-Postmodern-Thought-Theologicarum-Lovaniensium/dp/904292120X
This is an interesting book by a preacher who uses post-modernism as a means of luring in nonbelievers.
Preaching After God: Derrida, Caputo, and the Language of Postmodern Homiletics
http://www.amazon.com/Preaching-After-God-Postmodern-Homiletics/dp/1610974980/ref=la_B002V6NC4W_1_2?ie=UTF8&qid=1363290892&sr=1-2
There is also
Postmodernism, Reason and Religion
http://www.amazon.com/Postmodernism-Reason-Religion-Ernest-Gellner/dp/041508024X
But that doesn’t seem to go into the effects in any depth.