Well i studied to become a Social Studies teacher in the US. Also, there was an online program for Teaching English as a Foreign Language certification where you complete the coursework, then all you have to do is get someone at the school you are working at to observe you, submit the paperwork, and you have your TEFL.
If you prefer the full time classroom experience for getting your TEFL, there are several TEFL certification schools throughout Mexico, just have to google them.

...as far as getting jobs, it really isn't hard at all. You have no idea how bad they want native english speakers to teach English. Not only that, but there are jobs in other areas where they want people with English skills.

The process of finding the jobs isn't too difficult. Like I said, there are websites with the jobs on them...plus you can just e-mail schools and explain your situation and even if they don't have anything open, they can refer you to someone who does. The real issue is finding the pay you want...that requires searching around and you have to ask them directly. There are ones that pay 50 pesos an hour and others that pay 160 pesos an hour, and there are better paying schools out there....but those ones want x amount of experience (for example, the American School of Puebla).

But I'm not kidding, there are so many little schools and big schools out there.

As far as Puebla goes....living in the north was totally out of the question, or living in Michoacan or Guerrero. Getting a job in a beach town like Cancun or Puerto Vallarta is extremely competitive, because everyone seems to want to work there. I checked out the crime rates and the murder rates, and Puebla was pretty low on everything...there is also a lot of people from the north of Mexico that are fleeing the violence and going to the south of Mexico...so there are plenty of service related jobs. It seems like the border cities are going to become like detroit, as all of the manufacturing jobs are moving south as well.