Billy Mullis - Coyote - worked for the North America section of RBI from 1961-77. During that time he extentivally interviewed WaBun Inini of the American Indian movement (AIM) for RBI. He has the recordings on his Coyote Speaks website.
Coyote has kindly offered to help with some of the history of RBI.
StimmeDerDDR
Check out the "Where are they now?" posting for more about other RBI broadcasters.