Brazil is a very extensive country and you'll need some time to get to know all the crags around here. Historically, climbing development started on the southeast, but nowadays we have lots of potential on northeast and central-west areas as well.The type of rock will vary from place to place (ex: granite in Rio and Espirito Santo, limestone and quartzite in Minas Gerais, and so forth), pretty much for all tastes, from world class bouldering up to 2000ft big walls. The weather is best for climbing after summer (around May-Oct), when it is less rainy and colder. Brazilians are very welcoming and easy going people. Each state has its own culture, great local food and beautiful landscapes. English is more likely to be well understood in the biggest cities as well as among the climbing community.
To get information about climbing in Brazil you can read about some crags on http://www.escaladacafe.com.br/mapa (it's in portuguese but you can use google translate).