The best place to teach in Peru is Cusco. As the center of tourism, this city offers the most opportunities and the best living conditions. There are various places to teach, including the University there, but the best one going is a true 'Native English' group called Maximo Nivel. The institute is right on Avenida El Sol a few blocks from the main plaza. Definitely worth checking out, though I was told they prefer people who have graduated from their own TESOL certification program. Anyway, maybe it'll be good for you.