I've spoken to a few EFL teachers and they basically say that anybody you work for also has a certification course, usually about a month and costing around $1000 USD. I'm actually doing the work-study with LanguageLink (No certification required, they pay you to teach part time and you also take Russian lessons), at the end of which you get some kind of in-house EFL certification. I'm not sure how useful this is with other universities/companies, but I would imagine that if I wanted to do another contract with LL their own in-house certificate would be sufficient.

tdk