Neobr10: I dont know if i can be entered into the contest, but i would love to. Ive never donated to an international charity group such as the ones mentioned on this thread. However, i do donate every month to a local charity group in my city called ASCOMCER which treats people with cancer. I donate R$ 30,00 monthly (something like 18 dollars, not much really).
Its one of the only charity groups i trust, because i can really see that the donations are being used for people that really need assistance. Their work is really amazing. They have a good hospital which is a reference in cancer treatment, and they keep improving it.
And thanks for the giveaway, it was a great idea to encourage people to do something for charity.
Those are good charities too, in fact they usually have the lowest overhead (but not always).
I couldn't find the site I usually use to rate charities, but
http://www.charitynavigator.org seemed like an okay stand in.
For example, compare the American Red Cross to IFAW (IFAW has a 25% overhead or so, which is pretty high in my opinion but pays it's CEO 1/3 of what the Red Cross does).
I do like Child's Play and there's lists of charities with 1% overhead (or less) out there. Sadly too many charities are more into business than into helping.