I had to look into it for a friend that was coming to florida with me. You must have a visa if you have any sort of conviction to enter the states, even if you have been arrested and not charged and even if you have been done for driving offences!! I dont think there is any guarantee for entry to the states unfortunately. They are very strict and stand for no messing upin entry to their country. I have been there a few times and if you need any more help just post a question!