What started as Working Weekends On Organic Farms, has evolved to World Wide Opportunities on Organic Farms or Willing Workers On Organic Farms.  Whatever you call it, WWOOF is an educational and cultural exchange program. WWOOFing is a way to learn practical farming skills, be part of the organic agriculture movement, and experience the heart of Brazilian agrarian culture. 

The Fulbright U.S. Student Program is the largest U.S. exchange program offering opportunities for students and young professionals to undertake international graduate study, advanced research, university teaching, and primary and secondary school teaching worldwide. The program currently awards approximately 1,900 grants annually in all fields of study, and operates in more than 140 countries worldwide.

IFRE Volunteers is one lower-cost volunteer program operating in Brazil where volunteers can work with Brazilian youth in athletics programs or teach computer or handicraft skills.

You can also conduct your own search to find programs where you can study, intern, volunteer or just go abroad.