A free ebook which can be used to teach the topic of ethics in anthropological research is now available online:

Global health research in an unequal world: ethics case studies from Africa
Aellah, G. Chantler, T. Geissler, P. W.

Access the free ebook here: http://www.cabi.org/cabebooks/ebook/20163308509

In particular, please see:
• Chapter: 4 (Page no: 33) Friends like how?: getting personally involved with participants.
• Chapter: 39 (Page no: 200) Do anthropologists know best?: relationships between social scientists and medical researchers.