If you want to teach in a public school setting, you must be licensed by your state. Teacher certification is usually a multi-step process with levels of certification ranging from emergency licenses, which are issued when there is a teacher shortage, to full licenses which must be renewed periodically. Every state has different requirements for getting a provisional license, which is often the first step to a teaching career. However, the usual requirements tend to be the same across the board.
Contact your state's department of education to find out exactly what requirements are needed to teach in your state. The department of education is the agency normally responsible for teacher licensing. Find out if the subject you want to teach has a critical shortage area like bilingual education or special education.
Earn a bachelor's degree from an accredited institution, if you don't already heave one. A degree from an institution that offers a teacher preparation program--which offers student teaching and includes passing the relevant state exams--is usually not necessary for a license. You should have a bachelor's degree in the field in which you want to teach. The normal amount of time to study for a bachelor's degree is four years.
Pass a statewide test for teaching. Nearly all states require teachers to pass a state-licensing exam like Praxis 1, administered by Educational Testing Services, the same organization that administers the GRE. The test takes 2 to 2 1/2 hours to complete. To find out which tests your state requires, click the "ETS: For Test Takers" link (see Resources) and then click on the drop down menu under State Testing Requirements to select your state. Click "Go." There is normally a small fee for taking a test: as of December, 2010 the computer testing fee is $80.
Apply to your department of education for a teaching license. You'll need to fill out an application and pay a fee. The fee varies from state to state; expect to pay about $50 for an initial license. Processing times will depend on your state: expect to wait at least one month for a license.