Most analysts have agreed that was the main reason for Obama getting the prize. I think that while it is a nice sentiment, it defeats the purpose of the Nobel Peace Prize, which is to award achievements, not possible achievements. It would be as if they gave the Nobel Prize in Physics to a physicist for a brilliant idea but before that physicist performed the experiments that would show how their idea is supported by the data.
Obama has great potential to effect change for the better but it still remains to be seen whether he can or will, and awarding him the Nobel Peace Prize will only serve to heighten people's expectations of him. Even I think people are beginning to place too much emphasis on his ability to change the world are placing him on too high a pedestal.