The new eBooks Authoring page on Adobe.com provide detailed how-to guides and video tutorials on creating eBooks with InDesign.
InDesign is an excellent way to author eBooks compatible with a variety of devices — from PCs and smartphones to dedicated eReading devices like the Amazon Kindle, Barnes & Noble nook, and Sony Reader. Take a look at these how-to guides and video tutorials to learn how to create eBooks in InDesign and output them for viewing across screen types. Again, here’s the eBook authoring link.
In addition, InDesign Magazine made available part 1 of Gabriel Powell’s excellent article on using InDesign to create eBooks.