The best is to turn over all the info that you have collected on the attacks. Mind you theres times where I would like to take the law into my own hands and zap these @$$holes but unfortunatly that is frowned upon by the law and you could get charged even though you were just returning the favors by DOSing their systems. I dont have a lot of faith in the law but at times it is the best way to go also send the info to the server that the hacker is using they maynot be able to do much but you never know.