Cyberbullying could be anything from the traditional bullying of name calling to intimidating somebody online. Stopbullying.gov is a really good federal website that has a treasure trove of bullying information on it. I would say the best thing to do would be to report it to the school first if it's got any involvement with other students. You can also report the bullying to your local law enforcement as well if the bullying rises to the level of an actual crime.