I loved the book Intertwined, by Gena Showalter. See my review for that book here. It's a great story about a sixteen-year-old boy who has four human souls living inside him. Great, great book. Seriously. Loved it!
Now the sequel is being released SOON!!! Check out this really cool link!!! (and I get credit in a contest for an e-reader every time someone clicks on it, so PLEASE click on the link below!!!)