To STOP bullying... very little can be done, honestly. Just like there's little to be done to prevent one person from murdering another. But like committing murder, there are ways to handle the aftermath. There are ways of providing counseling or help groups for meeker students, there are ways for teachers to better keep an eye out in the future if they know that one student has been regularly picked on, there are ways bullies can be punished if there's sufficient accusations against them (ie, multiple people having been picked on, someone having witnesses, etc, etc).
As far as criminally charging... Perhaps, perhaps not. I'll let the courts argue that one, as extreme as it sounds. If one person abuses another to the point of suicide, there has been cases where the first person is charged with murder, and I believe there are several laws out there about cyber-bullying now.