This is usually regulated at the state level. Different states have different rules and inspection procedures, but recently the trend overall has been toward an easing of regulations for small entrepreneurs. However, there will always have to be rules both for sanitation and for labeling, to protect consumers. You should contact your state department of agriculture to get started. I've added some links below where you can read more about it.
The information in the links may seem a little overwhelming, because there's a lot to know. I would suggest that you go to a local store that carries some home made type foods, and contact one of the producers to see what their advice is before you get into the project too far.