Pat Flynn of the Smart Passive Income blog has a free e-book available for download that covers all the details of writing, publishing and marketing an e-book. I don't believe he pushes recording as a way to write the book. He does say that you can increase sales by having an audio version of the e-book recorded once the book is ready to release.
He covers converting your manuscript to a PDF, security, automating sales, pricing and much more. I found the book very informative.

