GreatAuPair provides several options for legal visas worldwide.
A family or an organization may sponsor a student from nearly any country to come to the U.S. to study. The student may live with the sponsor as a member of the household, helping with assigned duties and chores. Student visas may be granted for stays up to four years and are otherwise extendable.
A sponsor agrees to pay for the tuition and housing for the sponsored student. Students are required to complete 12 credit hours of coursework per semester, from an accredited school, to maintain their F-1 status. The annual cost of tuition is approximately $4,000, but may be more depending on the institution selected.
The H-1B visa is restricted to those jobs that require the applicant to have attained a bachelor's degree (or higher) and cannot be issued for an "au pair" position, but may be issued for the position of "educator" such as for a home-school teacher or linguist that has the specific skills and credentials that meet your particular job description. The H-1B visa also stipulates that the "employee" must be paid the prevailing wage for the specified job
The H-2B visa is available for nonagricultural, unskilled workers who are needed to fulfill a demonstrable temporary need.