The above comments are all excellent, which in itself says something FOR your site so far. I think we like your writing style and your charisma and authenticity transmit well enough that the comments are right on target.
Currently the first 'download trial' button isn't working in Firefox 2.0.0.1. Yeah, that's not a whole lot of 'help', but its something concrete.
On the marketing thing, I'm definitely no expert, but it seems to me that your download-for-free (then pay later if happy and/or don't cancel payment) model might not be the most profitable, near or long term. Its generous, and follows the idea of 'free at first, for publicity', but seems a little risky in eBook form. Or maybe its not that. It just seems a little off somehow.
Perhaps giving a chapter or two 'on trial', with the rest either unlockable with purchase, or downloadable in installments? I don't know what the fashionable eBook business model is these days, but I'm sure you can do better than the average eBook.
Good luck with your book and keep up the great blog. It makes great reading.
-Smack