The types of visas issued for Brazil are:
transit: for tourists in transit who wish to leave the airport between one flight and another, basically.
tourist: for recreational stays and visitations, not work. These visas allow stays of up to 90 days after which they can be extended (prorrogação) once at the nearest department of the Policia Federal before expiry date.
cultural or study trip: for conference attendees, researchers, etc., with maximum duration of 2 years with extension period, insofar as conditions for issuance persist.
business trip: for those who wish to do business in Brazil without immigration. Duration of up to 6 months per year, for a period of up to 5 years. Can be extended like a tourist visa.
student: for students of regular schooling (primary, secondary, etc.), this visa does not allow paid work and is valid for up to 1 year, with extension according to school year. The student should renew 30 days prior to expiration, and cannot change course without issuing a new visa.
work: for foreigners that come to Brazil to work in Brazilian companies. Work permit is issued at the Ministry of Labor (ministério do trabalho e emprego) needed for issuance of a work visa. Up to 2-year duration with extension for equal period and can be transferred to permanent visas.
journalist: for correspondents of media vehicles who receive their salaries from abroad. Extendable 4-year duration.
religious missions: for members of official religious organizations, 1-year duration with possibility of equal extension or transfer to permanent visa.
permanent: for foreigners that want to remain in Brazil. Requires prior authorization of the ministry of labor, under regulations of the Immigration Council, and issuance of RNE (registro nacional de estrangeiros) at the policia federal.
Note: Requirements for application of permanent visa are: amnesty, Brazilian offspring or marriage. In the case of Brazilian offspring, the applicant needs to go to the nearest Policia Federal department with valid passport and the child´s birth certificate. It´s a pretty simple process that takes about 3 months. The applicant must have a valid visa. In the case of marriage, the applicant will have to ask someone back home to get a criminal record statement (certificado de antecedentes criminais) at the local police department, and have it translated by a sworn translator in Brazil.
To get married in Brazil, you need to prove marital status in the same way, and have the statement translated by a sworn translator in Brazil. It´s a good idea to get this done before you leave your homeland.