For micro loans, one source would be
Kiva.org - Loans that change lives. Kiva has the advantage that you see directly where your money goes.
Then there is the Grameen Foundation from the guy who got the Nobel Peace Prize. That organisation does also some "goose that lays the golden egg"-work. There is one
Ted video from one of the projects.
On the other hand I also can't point you to good data to base your decision on.