Most charitable work is done through Catholic charities, I believe CARITAS. I don't think they will care about your religion if you want to volunteer. I know an American Jewish philanthropist who told me that he gives money to Caritas in Argentina (he does business there) because he said that if you want to help the people in Argentina, the Catholic Church is the most effective organization. There are soup kitchens and other social outreach programs in the villas. I know someone who teaches children in the villa how to play musical instruments.