In Florianópolis, I went quickly at the Organic Market (Wednesdays at the Federal University of Santa Catarina -UFSC) and Saturdays at the Lagoa da Conceição and met Mauro Schorr from the Instituto Anima which produce herbs, artcrafts and it did sounds a good place for me to return and experience. They offer permaculture courses, massage and you can choose to wwoof or pay for your accomodation (R$40/ Dec 2008).
More info: http://www.institutoanima.org/
In Garopaba, there is Gaia Village.
Gaia Village is a private project focusing in sustainability.
The aim is to create an example of ecosystem where the human interact friendly with the environment from the perspective where Earth is Gaia; a living system.
Since 1998, they are active in the local /regional sustainable developemnt with several programs and partnerships. Monthly, they have a get together at sunset to exhange ideas.
Go further and see the reports of what is happening: http://www.gaia.org.au/
I am sure there is plenty more happening at Santa Catarina, if you know a community or project, anything that is making the world better; please send it as I will happily spread the word……..