The website Teach.com contains extensive information on how to become a school teacher, as do state-specific government and educational department websites. The California Commission on Teacher Credentialing at ctc.ca.gov offers information for perspective teachers in that state, and similar programs operate in other states.
Teach.com also provides information that is state-specific so that perspective teachers know the requirements in their areas. The site provides information on current teacher salaries and benefits, credential programs, and opportunities to gain a master's degree in education. State sites such as the CTC or the New York State Education Department can explain the requirements for teaching elementary school and high school, as well as the requirements for special education and substitute teaching.