I'd always heard a university degree (BA, BS) was required... in the US, that is usually four years. I haven't heard that two-year college degrees (AA, for example) are eligible or that having TEFL or TESOL makes a difference in regard to visa application as long a school was willing to sponsor you and you had a uni degree. I have heard of folks who managed to get around the uni qualification one way or another but I can't confirm exactly how they did it. I don't know if there are standard qualifications for non-uni applicants. If someone's got a current, definitive answer, please let us know.