What can be done for a bad overbite?

Depends on severity : It depends on the severity and age. Early intervention in a child can improve the bite and face to acceptable. Severity in an adult will most likely need orthognathic surgery to correct it . http://en.wikipedia.org/wiki/overbite for more info.

Rx: Put teeth, jaws, or both where they belong. Usually requires orthodontic treatment. Sometimes (for non-growing patients) orthodontic treatment and jaw surgery. There are an infinite number of solutions, based on your personal malocclusion. You can't buy an "overbite fix" package off the supermarket shelf. Go see a real orthodontist to discuss individualized needs and solutions.