In her own words, here.
It's called The Short Second Life of Bree Tanner, and it's about one of the vampires in Victoria's not-so-victorious army.
So, that sounds fun! I'm definitely the type that will read it for free online. It will be at www.breetanner.com from June 7 to July 5.
The book itself will be released June 5, and "One dollar of each book purchased in the US from the first printing will be donated to American Red Cross for their relief efforts in Haiti and Chile and other parts of the world where people are in great need." There will also be an online donation option.