Look up your state's department of education and/or teacher credentialing commission (as some states call them) to find the requirements. Most places will probably require an undergraduate degree in art, then you will probably have to take some sort of mastery test and apply for and complete a credentialing program for the education piece. Student teaching will probably follow.
Another idea is to call up the human resources department in some local school districts to see what they are looking for in your specific area of teaching. Many districts will take anybody who can teach math or science due to shortages. They may be looking for more in art; I couldn't really tell you.
Got any connections at private schools? Oftentimes no credential is necessary.