If the Curiosity Rover on Mars detects life, perhaps a primitive bacterium, what will be the reaction of the Fundies? My guess is that they will deny it for about 5 years and then try to suggest that God did it to test our faith.
I thought, they said in the media that Curiosity is only able to detect the "building blocks of life" but not life itself.
As about the religious people and their reaction ... it depends on the religion, I guess; muslims and christians will probably claim that their deity created life on many worlds and that their deity's intelligent creatures on those worlds believe in their deity as well. A claim that is untestable with current technology. They will probably also claim that their deity might have revealed itself in different corporeal forms on these worlds. If the aliens look like octopuses, their deity would have looked like an octopus and so on.
I don't see them being really shocked about it. They are more creative and clever than that. In general theists love to make many extraordinary claims without proofs or at least some evidence.