Some other sources of information on organizations are: Digital Librarian, the Library of Congress' list of Kenya related organizations, and the
University of Michigan School of Social Work's links to many lists of volunteer and charitable organizations.

Choosing an organization is a tradeoff of one's money versus the time it would take to research who is really doing the kinds of work one wishes to support. It would be possible to spend many weeks or months to thoroughly investigate any of these organizations in "Charities Registration" sites (many states have them), or even in newspapers and magazines both from the U.S. and other countries. Hopefully, a sampling of a few different sites will at least give you a better sense of an organization's reputation.