If you live in the US, got to the USA Boxing website. There are regions for all parts of the country. I live in the Northeast and the guy I spoke with said they were desperate for officials for amateur fights. The membership is about $40 and they run seminars for judges, referees, etc. The local region will then have you judge some taped fights to see how you'd score them. Once you have been approved you can start working amateur bouts. You don't get paid, but it's a place to start.