WWOOF means World Wide Opportunities on Organic Farm, it’s an organization created to share ideas of sustainable ways of life. The website links volunteers to host farmers, the volunteer will work for the host and the host will provide accommodation, food and teach organic production methods.
To become a WWOOFER you may access the WWOOF organization of a country and register, the price depends on the country, the american WWOOF the lowest fee is $ 30. Once registered you’ll have access to the farms directory, this way you can choose the farm you want and contact the farmer to check if he needs help.
It also might be a good way to practice your English!