Hi Dusty-

Good questions. For you and how you conduct your own personal classroom prep work, a TEFL certificate may tend to be a formality, especially if you have actual previous classroom teaching experience. You'll find that many, if not most, TEFL teachers have had no actual classroom teaching experience prior to climbing off the airplane.

Sometimes, depending on who you work for, a TEFL certificate will garner a bit more in wages. But the way in which you gain more in pay is being able to be more selective in the jobs offered to you. All the education and experience in the world may not do you much good in landing a job if you don't have a piece of paper that actually says "TEFL trained."

In Asia, TEFL is a bit of an unregulated and somewhat unsophisticated system. You personally may hold professorship at a major North American or European university, teaching English or literature to diverse populations, but without that TEFL cert you may find yourself standing in line with fresh college grads pandering for whatever gets tossed your way. Often, universities in the west just don't have the same brand recognition elsewhere.

On-line TEFL training programs aren't worth the electricity used to boot up your computor. I've worked with a few teachers with this training, and it provided them nothing, except the paper it was printed on. Bu there are a number of one to three month programs that give you a lot of good info about teaching techniques for special populations, and some thorough grammar review. There are some distinct differences between how you would ordinarily teach native English speakers and how you would approach ESL students. Also, if you can do a training program in a country or culture in which you'd like to teach, you gain a lot of insight toward cultural approaches. One of the biggest stumbling blocks for most TEFL teachers are the problems associated with differences in cultures, as you can tell from so many of the posters and threads in this forum.

Good luck with your endeavors.