Becoming TEFL/TESOL certified?

Does anyone know what the best (most employable abroad) way to become TEFL/TESOL certified is? I know master’s programs exist for TESOL, but the 4-week TEFL programs that can be completed abroad are much more appealing. Does anyone know about employability for these? There are a lot of these in Europe. Will they get me a job in other countries as well? Teaching English abroad (preferably in less-overrun countries: think western Europe and MENA) is something I’m considering for after graduation as a fairly directionless linguistics major.