Having being built by immigration, Brazil is a very foreigner friendly country. As far as employment opportunities go you have 3 main options. They are: Employment by a firm in the formal economy; work as an unpaid volunteer for an NGO, work as a private teacher.
Your only barriers to working formally are the need to speak Portuguese, have relevant work experience, the correct visa status, and to pass through the application process. The most likely sectors to do this are in Finance, Banking and I.T. If you already work for a multi national the best way is to just ask for a transfer. If you don't work for a multi national the best place to start is the web site of Brazil's largest national recruitment agency. www.catho.com.br Be aware that firms will prefer to employ Brazilians over foreigners due to high unemployment and don't expect an advanced economy salary. It is hard for foreigners to find a formal job in Brazil.
Working for an NGO in Brazil normally involves you paying them for a stint a on their project. However there is still the NGO's application process to go through so it's not a question of turning up and paying to join. The better ones will require you to have very specific work experience. There are lots of NGO's to choose from all involved in very well meaning social projects so if you want to make a difference this is a excellent way to do so. See the website voluntarios.com.br
The favourite occupations for foreigners in Brazil are private language tuition (English / Spanish and German are the most in demand), and private teaching of I.T. skills. The latter is now in more demand than the former due to few schools having computing departments. You can expect to charge anywhere between R$20 to R$50 per hour for private teaching. Place an advert in the classifieds section of your resident city's news paper to get started. Please be aware to maintain your legality of private employment you will be required to file a tax return.
It's important to note that as an emerging economy the whole work ethic / life balance concept that you are familiar with in North America and Western Europe is different in Brazil As a network society your success will depend more on who you know rather than what you know. The good thing about Brazil is that it's cheap enough to stay for 6 months without working to see what opportunities you can make for yourself. Any kind of job is easier to find in São Paulo as the aggregate wealth is higher and it has a larger population than the other cities.