Thanks for the interesting links chaps.
20% (coindl) and 10% (bitcoinservice) off the top seems a bit excessive for, essentially, a web server and a bitcoin address. Even more so given that the "service" seems to be the supply of a associated bitcoin-funded account, which is only necessary because that's the only way they can get their cut.
For low volume, I wonder how much trouble RodeoX's suggestion of emailing a PDF would be. It's not like I expect to sell thousands of copies (if any).
As an additional question: is there anywhere one can go to buy books-for-bitcoins?
I'd suggest listing your e-book on Amazon's marketplace, then placing a mention in the description that you can purchase via Bitcoin by email.
Best of both worlds really