The website below has a very good overview of TEFL qualifications, so if you are a bit unsure of what kind of qualification is the best one for you, have a look here first:
You will also find a lot of useful information about jobs there and other EFL issues.
The TEFLboard might be a good reference to add to your Overview of TEFL Qualifications section.
It's an international teacher training program directory which compares curriculum details of different qualifications.
Hope it helps! Katie