There have been numerous threads on this. Look for one about teaching English in Taiwan.
For Latin America, they usually prefer ESL certificate courses such as the Trinity College TESOL course and the Cambridge course (offered at many locations now).
For Asian, advanced degrees are preferred, though not necessarily in ESL.
Read this book for an in depth look at national requirements, certifications, and specific schools:
Amazon.com: Teaching English Abroad, 8th (Teaching English Abroad): Susan Griffith: Books
And Dave's ESL forum is world renowned for ESL information. It has just about everything from it's own forums for each country, forums for teachers and forums for students. It also has sample lessons and English info for students and teachers.
Dave's ESL Cafe
To answer your question, you can get certified whilst away and it might even be cheaper, but you will need money to live on while you certify and you might need to return home in some cases to get a work visa (laws vary).