Hey lhunter-
How many of these signups are you thinking you will get?
If it is going to be 15-25 per day, i would recommend doing it manually...essentially telling them to please signup (which they can do in the V4.0 without buying anything) and then email the e-book to them when you see they have signed up.
If you expect to get more than 25 per day, i would talk to John Larson in our custom programming department and have something programmed to handle this. If you are getting more than 25 per day, you probably won't mind paying a bit extra for this feature as it would save you time and money in the long run.
-gup