Kidthing was something I read about on the No Limits 2 Learningh Blog. Kidthing is an interactive reader for digital books. The reader is available to teachers at this link: Kidthing. The books are available for download each month, different books each month. Some titles have been by Dr. Seuss, National Geographic and more.
At this time the reader is available for Windows only (XP and Vista), but they say a Mac reader will be available by the end of the year. Looks like a great little item for any classroom with a computer!