Haiti. Already the poorest nation in the Western Hemisphere, plagued by poor governing, over-exploitation of resources, and ignorant comments by religious figures, now this earthquake. Help them out a bit, whether it's by sending money, sending prayers, buying Haitian music, or denouncing bigotry that labels Haitians as devil-worshipers or worse. If voodoo is a sticking point for you, read more about it at wikipedia (you might be surprised to learn that it's monotheistic, for instance).
To help directly and immediately, text "HAITI" to 90999 to donate $10 to Red Cross relief efforts in Haiti. You can read more about the effects of the earthquake and ways to help here.