More than once, I have taken mainline Christian churches to task for failing to stick up in public for there more humane version of the Christian message than that of the fundamentalist Christians. It wouldn't convince me, but it would, at least, mark them as a legitimate voice in the culture wars waged mostly between secular people and the Christian Right. But, actions speak louder than words sometimes, so I want to call attention to some action in my home town of Oxford, Ohio, a place with no special connection at all to the Gulf Coast.
"On Sunday afternoon . . . a Katrina benefit concert [was] put on by Methodist, Presbyterian, Episcopal, and Lutheran church choirs.", via an e-mail from my father.
I also want to note that the effort was ecumenical (which means involving multiple religious groups). I think that you will be seeing mainline Christians turn to ecumenical approaches more and more as it appears that they are having a hard time generating sufficient critical mass acting alone and have increasingly common goals as dissenters vote with their feet rather than trying to change these institutions from within (not that there aren't currently such internal feuds going on as well).