Having taught in Buenos Aires in 2005, I feel that I can offer some sound advice on the situation of foreign teachers in Argentina as well as some of the possible dangers and pitfalls.
Firstly, I found that presentation and physical appearance are of the upmost importance in Argentinian culture. The television relentlessly emits images of beautiful, slender young people, and in regards to teaching, you will do well to dress yourself professionally in a suit or in attire that makes you look like a teacher and not like a tourist. This sounds trivial, but if you go to a job interview dressed in a pair of shorts or in sandals, the schools will not take you seriously, and neither will the students.
Secondly, it helps to have teaching qualifications, such as a TEFL certificate, but these are not necessary all of the time. Some schools to be recommended are Brooklyn Bridge and Sol Vazquez Educational Consultancy. These schools teach business english, so you will be expected to teach business executives and employees, often in locations outside of the city- so get to know the local metro (subte) system or get a bus guide!
As regards payment, you must not expect to make as much as Japan or the Emirates. In general, you are
paid about 500 pesos a month, and it is up to you to find accommodation. For many, this means living in a hostel, as apartments are hard to come by! As most foreign teachers are illegal and do not work with a visa, you will have to travel outside the country every three months to renew your tourist status. The lack of support can be frustrating,and if you can it is advisable to learn Spanish. Although many local portenos still can cheat you with prices, at least it enables you to gain access to the culture and avoid being cheated excessively!
Buenos Aires contains most of the work opportunities in Argentina, but if are interested in the other cities, Mendoza and Cordoba have some language schools as well!
I loved my experience in Argentina, but my final and most important words of advice to foreign teachers wanting to teach there are to be resilient in the face of adversity and have your return ticket paid for being embarking upon your journey to the Argentine Republic.