Kamehameha Schools Distance Learning is offering you a FREE course to celebrate Earth Day in April. This course is well laid out, very content rich and an eye opener.
http://bit.ly/malama_aina (not to fear I did the url shortening) Check out samples of the course by clicking on the lo'i, fishpond or sky.
Registration deadline March 15. Course runs 3 wks in April but you have a year of access to the materials.