April, can't you just buy really cheap hosting somewhere and put an email auto-responder on it? I have several domains hosted on two providers (so I get email even if one is down), and it can be done really cheaply. Someone here could probably write a simple PHP script that will generate a link that's only valid for 24 hours, or for the original IP, or whatever. Running that on a $5/mo web host would be simple.
I don't know, but my impression was that most of the file-sharing stuff is done by people collecting works into giant libraries and using BitTorrent. I really can't imagine pirates downloading one book at a time from your website - one of them will do that once, then collect and share. Google will show you a lot of those... "heinlein torrent" (
http://www.google.com.au/search?hl=e...inlein+torrent) finds a number of multi-gigabyte collections of science fiction, for example. Those are the ones that inevitably come up when I'm looking for ebooks.