If you're considering teaching English in North American, your best bet would be to contact (e-mail) the Board of Education in the State or Province of your liking.
If you're interested in teaching English as a Foreign Language (EFL) in Asia or other non-European countries, you could check out the various on-line sites that offer TESL (Teaching English as a Foreign Language) courses ($). It's a start . . .
Best of Luck!
- For Teachers