Good question glo!
At first glance, I would be tempted to answer 'no': that science does not in itself help us become more moral persons. Knowledge can be used to do both good and evil. In the end, however, if you believe that humans are inherently more likely to be good, then the answer would be that overall science is likely to help us to become better human beings, simply because it provides us with the knowledge we need to make difficult choices that may have moral implications. If, on the other hand, you believe humans will only abuse this knowledge for personal gain and selfish reasons, then IMHO it would rather have a negative impact on our morality.
I overall have a fairly positive view of humans, so I'm leaning towards the former. This is not based on data though, it is simply my belief. Unfortunately, all positive examples I can think of also have darker sides. Take animal rights: IMHO better insight into animal behavior, psychology and biology have led to an increasingly strong animal rights movement, simply because of an increased understanding that animals aren't necessarily in a different class from us. On the other hand, advances in science and technology have led to increasingly inhumane forms of industrial farming. It's almost as if at an individual level we use this scientific knowledge to be better humans, but at an institutional level we also fail to weed out morally dubious options that science provides us.
So overall, I would say that science itself does not make our society as a whole more moral. However, a side effect of science, namely increasing wealth and prosperity, does put us in the luxurious position of being able to make moral choices more easily. IMHO the richer we get, the more likely we are to do what is right, such as care for the poor, protect those who need protection and preserve our environment for future generations.