For all US citizens coming to Brazil, you need a valid US Passport AND you need to have a Brazilian Visa to enter into Brazil. While it usually takes 2-3 weeks a Brazilian Visa can take up to 2 months to get, as you need to send your passport to the nearest Brazilian embassy (San Francisco for west coast pilots.) A Brazilian Visa is good for 5 years, but it has to be used for the first entry within 90 days of when it is issued. Here is a link to the Consulate General of Brazil in San Francisco. http://www.brazilsf.org/visa_tourist_eng.htm
