What about Habitat for Humanity?
They put families in houses which over the long run has an effect on the lives, education level and success of the children in the future. The Habitat for Humanity program doesnt just help the child or family but it actually breaks the cycle of poverty and gives them a chance.
I should note that I work for Habitat for Humanity and I just thought I would throw this out there. There are so many great charities and this is just one of many, you cant go wrong when helping children.