I agree w/ Notsoperfect, that it should be a collective effort. I think that bullying is much worse than many years ago. Parents are too busy these days to properly educate and spend time with their children.
I feel as though parents should be held more responsible than teachers and schools, as it is not up to teachers to raise the children. It is up to the teachers to teach knowledge, not morals.
However, teachers and schools should be punishing bullying more; should not be allowing it to continue. I think that if the schools tried to get parents more involved, and make parents aware of the situation, and maybe held classes on educating about bullying, then it would result in less bullying.