It was originally a story that she had posted online, and then a group of fans listed who they'd imagined for the faces/voices (although, that site has since been taken down), and Katherine Heigl was the face for Stitch. The book has since been removed from online and published, and it's really an amazing book. I recommend it. You may have to special order it, as most chain book stores don't carry it in-stock all the time, though.