Ken,For the most part the details of the transactions are provided by whichever payment service is used. You can use just about any payment service (ClickBank or PayPal, for example). The real bugabo is how to provid the registration code to unlock the ebook. A lot of people use Microcreations Automatic Payment Service, which provides the registration code to the customer immediately upon payment.
The alternative is to use a pay service (monthly fees) that tracks payments and relocks the book if a refund is requested (of course you still need to use ClickBank or PayPal). Gold Panner Software offers two solutions to address the refund issue. One requires a monthly fee and the other a one time fee. Not a lot of people ask for refunds so it is not uncommon for sellers to forego trying to relock books that have been refunded. It really becomes an economic issue if it is worth spending a dollar to save a dime.
The services that do track ebook usage (as well as relocking ebooks) frequently are an annoyance to the customer. You can find discussion about this elsewhere in the forum.
The question regarding a customer's request for key codes first needs an explanation on how the security system works. You have a possibility of a thousand keycodes. Which keycode will unlock the customer's ebook is determined by an algorithm that based on the serial number where the ebook is installed. With the possible 1,000 keycodes the liklihood that any two users will share the same key code is 0.1%.
In other words the customer can request a keycode a thousand times and it will always be the same. The only time it will change is if the customer installs the ebook on a second machine or replaces their hard drive. It is up to you as a vendor how replacement key codes will be handled.
Using Activ you can also use virial marketing. This is acheived by makeing a portion (that you select) to be viewed by the potential customer. After payment is made the rest of the ebook then becomes available. What is great about this approach is if someone gives a copy of your ebook to a friend the ebook is automatically relocked requiring a new license to be purchased for use on the friend's machine. (Okay, there is a 0.1% chance that the friends will share the same key code, but that is a slim chance.) The monthly pay services that offer a way to provide a key code as well as relocking the ebook dismantle the ebook entirely so the only way to view it is to purchase a keycode. These services recommend that you make two ebooks. One for purchase (which is entirely locked) and a second which is used for demo purposes. The system you select really depends on how you intend to market you ebook.
Microcreation
http://home.att.net/~microcreations/
Gold Panner's HyprLock
http://www.goldpanner.ca/hyprlock/index.htm
(Edited by Storyman at 12:12 pm on Nov. 13, 2005)