What are the steps on doing this? Do i need to be certified?

Every state is different; check with Zoning and your Secretary of state for licensing arequirements

Question: Are you going to do it on face-to-face basis or will you be using Internet only, doing translations as well?

Big difference in what you need. Certification is not as important as your delivered results.

I believe you can do it by just putting up flyer's around your community and make sure you put down your fee. I know a lot of people in the U.S. want to learn English but don't have them money to go to school.

My suggestion would be to speak to an accountant and a lawyer to check on the home-based business requirements for your area and also the best way to set up your business (eg sole operator etc). Also check with your local council or state government agency as there may be restrictions or special requirements for operating from home in your area. Many have websites that contain relevant information.

After you've got it set up, join some networks - local business leads groups, chamber of commerce etc - so you can get the word out. If no-one knows you're there you're not going to get any business no matter how good your service! :)

I would think that certification would only be necessary if you intend to give the students some sort of qualification at the end of the course.