At best 150, and most likely 148-149. He couldn't stay around that during training without eating a lot until training tapered off during fight week.
Some member of team pacquiao was interviewed by a pinoy crew moments before the fight and chino trinidad, a commentator for the pinoy HBO version of the fight along with brian viloria announced that pac was 149 lbs. They didn't have any idea how heavy cotto was.
I seem to AGREE Tom. It WOULD appear as though people THINK that their views are MORE important if they are expressed FIRMLY in capitals.