As for when the ebook is completed, you can setup a page that says Free ebooks on your site. Create a folder in your root directory, zip the ebook, upload to folder in control panel, and make the link a hyperlink on your page underneath an ecover/description of it.
or you can add them to a shopping cart which is a little more detailed and work involved.
Could be other ways but these are both the ways I have done it.
p.s. also don't forget about uploading your free report to sites like . I had my ebooks indexed with 24 hours. Faster than my own site. I also am impressed with how many people come and download!