Http://www.bls.gov/oco/ocos066.htm I like this site
he education and training required of postsecondary teachers varies widely, depending on the subject taught and educational institution employing them. Educational requirements for teachers are generally highest at research universities, where a Ph.D. is the most commonly held degree; at career and technical institutes, experience and expertise in a related occupation is the principal qualification.
Education and training. Four-year colleges and universities usually require candidates for full-time, tenure-track positions, to hold a doctoral degree. However, they may hire master’s degree holders or doctoral candidates for certain disciplines, such as the arts, or for part-time and temporary jobs.
Doctoral programs take an average of 6 years of full-time study beyond the bachelor’s degree; this includes time spent completing a master’s degree and a dissertation. Some programs, such as those in the humanities, may take longer to complete; others, such as those in engineering, usually are shorter. Candidates specialize in a subfield of a discipline, for example, organic chemistry, counseling psychology, or European history, and also take courses covering the entire discipline. Programs typically include 20 or more increasingly specialized courses and seminars plus comprehensive examinations on all major areas of the field. Candidates also must complete a dissertation—a written report on original research in the candidate’s major field of study. The dissertation sets forth an original hypothesis or proposes a model and tests it. Students in the natural sciences and engineering usually do laboratory work; in the humanities, they study original documents and other published material. The dissertation is done under the guidance of one or more faculty advisors and usually takes 1 or 2 years of full-time work.
In 2-year colleges, master’s degree holders fill most full-time teaching positions. However, in certain fields where there may be more applicants than available jobs, institutions can be more selective in their hiring practices. In these fields, master’s degree holders may be passed over in favor of candidates holding Ph.Ds. Many 2-year institutions increasingly prefer job applicants to have some teaching experience or experience with distance learning. Preference also may be given to those holding dual master’s degrees, especially at smaller institutions, because they can teach more subjects.
Training requirements for postsecondary career and technical education teachers vary by State and subject. In general, career and technical education teachers need a bachelor’s or graduate degree, plus at least 3 years of work experience in their field. In some fields, a license or certificate that demonstrates one’s qualifications may be all that is required. These teachers may need to update their skills through continuing education to maintain certification. They must also maintain ongoing dialogue with businesses to determine the skills most needed in the current workplace.