Homeschooling laws vary from state to state. In Missouri, a parent is required to provide some sort of education to a child between the ages of 7 and 17. The parent is not required to have a teaching certificate, but must meet certain regulations.
In California, any child between 6 and 18 must attend public school, private school or be tutored by a licensed, qualified educator. In New York, the parents must notify their local school district by July 1st of the school year that they plan to homeschool, and the child must pass a yearly test. Regardless of the age of your child, check regulations carefully and keep records, including examples of your child's work.
Enroll your student in an accredited online or correspondence curriculum. Check the accreditation listed for the school; not all accrediting agencies are created equal. Shop around, compare prices, and request samples of the curriculum. Call local colleges and universities to see if they consider graduation from these schools as valid for enrollment in their institutions.
Join a local homeschooling organization. Discuss with their members the options they have chosen for their children. Trade skills with other parents. You may be a math whiz, and your neighbor may be very good at English, while your neighbor on the other side of the street may be skilled in another language. If your state requires a licensed educator, pool resources with other parents to hire someone with the requisite requirements.
Plan for your child to take exams that will prove that he has learned the requisite skills to get a job or enter college. The GED, or General Education Degree, is considered the equivalent of a high school diploma. You may also wish to arrange for your child to take college entry exams, such as the SAT.