The Literacy Site supports Room to Read and First Book. All you have to do is go to the site, click a button, and view the resulting ads. There is also a store you can shop in and the profits go to buy books. I've blogged about both Room to Read and First Book and both programs are well worth supporting.
Snopes.com vetted original GreaterGood.com site The Hunger Site, so you can assume your daily clicks are actually helping to buy children books.