http://www.charitynavigator.org/ is a site that has looked interesting to me, but I'm not sure they have exactly what you need. As for me, I know exactly the kind of charities I like. That is, cystic fibrosis and public radio. So I just donate to things that speak to me. Not even the CF foundation, but individual cases. And with public radio, I have favorite local stations (in my media market and others).
"For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring." - Carl Sagan
