TeachAbroadKorea.com is a reputable agency located in Salt Lake City, Utah. The management at Teach Abroad Korea is American, but can be summed up as "Korean experts," having lived in Korea, learned the language, and know the country inside and out.
https://www.youtube.com/user/teachabroadkorea

We are searching for outgoing and adventurous people who want to make new friends, help students learn and have an adventure of a lifetime! In addition, the four following criteria must be met.

*Be an American or British, Irish, Canadian citizen who speaks English as their first language
* Bachelor degree from an accredited college or university in any subject
Clean criminal history
*Be mentally and physically healthy

Must prepare the documents as below:
A criminal record check with an apostille (UK,Ireland, USA) - valid for 6 months
A copy of diploma with an apostille (UK, Ireland, USA)

A notarized criminal record check from the Korean consulate - Canada
A notarized copy of degree from the Korean Consulate - Canada
Salary and Benefits