Here are links that we like
http://www.amref.at/
http://www.amref.org/
http://www.samaritan-village.org/
www.volunteer4africa.org Volunteer 4 Africa provides free and low cost volunteer work opprotunities throughout Africa.
http://www.outdoor-unlimited.at/de_index.html
http://www.tanzania.at/
The beach crab resort, Pangani