Try http://joyjobs.com/. Though is more of a page to look for international teaching jobs I think there is a list of schools to look into. It posts vacancies on a daily basis for schools all over the world. Hope it helps

Thanks on the reply!!!!

I'm thankful I bumped into this comment about Churchill School since I recently received an offer for the middle school. I would really appreciate it if you could give me more details about this school regarding students' discipline, treatment to teachers, living in the area, etc. If by any chance you know someone who's working there right now even better so I can have a better insight of what the school is about. I really want to make an informed decision since it is a big deal for me to move to Mexico City and start a whole new experience in my life.

Thanks in advance!!!!!! :)