If you want to make a donation to help the poor people of Haiti, then do so. There are many reputable, international aid agencies working there to choose from. To entice people, and connect this terrible tragedy with the offer of free books, or anything else is, I think, obscene. Here is a quote from the site Nate referenced, which speaks for itself:
"This is a chance to do some good for people in need—and even if you couldn’t care less about the plight of Haiti, the opportunity to get nearly $1500 worth of RPG e-books for $20 is worth seizing for its own sake."