[QUOTE="impsmith;38403841"]Your question is very difficult to answer, because you're asking about a job which is available in virtually every country whose first language isn't English[/B], and there are literally thousands of different jobs even within single countries. Where do you want to go, and which age group do you want to teach?
In short: you can get employment after doing any course, or no course at all. For most countries' visa requirements, you'll need a degree. For some countries, you might need a one-month TEFL certificate, or a degree in a particular subject. For some jobs, you need a masters, and sometimes, it needs to be a masters in TESOL. For some jobs, you need five years' experience. If you want to work in some places in China, you need to be 24, with two years' post-graduation work experience (sometimes in TEFL, sometimes not).
The one-month 130-hour course looks a lot better to any savvy employers than a bull**** weekend or online course. It's more difficult than university, in my opinion. It's a real qualification. From Wikipedia:
"The qualification is awarded upon passing a course which includes supervised teaching practice and written assignments, and is accredited in the United Kingdom by the Qualifications and Curriculum Authority at Level 5 on the UK National Qualifications Framework. The Trinity CertTESOL is widely respected and recognised by language schools around the world". The CELTA is the same, and it's similarly respected by employers. You'll find a job more easily, and you're more likely to find a better job, if you have the one-month course.
HOWEVER. Rules are made to be broken, and that's more true the further away from the 'developed countries' you go. If you find a school that really likes you, they'll probably be able to bend the rules, or you could just work illegally on a tourist/student visa.
I agree with almost all of this but the exception is in bold- it's a common misconception that almost every country has a TEFL industry- simply not the case. The ability to sustain a TEFL industry depends on having a local population able to pay for it, and for this reason there are virtually no TEFL jobs across swathes of Africa as well as certain parts of Asia. Similarly, in countries where the quality of English teaching in state schools is excellent (i.e Scandinavia) there is little/no demand for TEFL teachers.
Also, there is a huge TEFL industry in English-speaking countries. Obviously only those jobs in the UK, Ireland and Malta are really open to UK job seekers as working in the US, Canada etc requires the appropriate visa. People have done it before though.