The consensus around here among the scanners tends to be that, since the content is merely a reproduction of a work (even when scans have been repaired or otherwise modified), the scanner has no rights to the scan (legally, this is backed by a clip art case against Corel, as I recall, which held that labor, costs, and reconstruction don't constitute "original art" to be protected).
Many, however, would still appreciate hearing from you, rather than having some anonymous guy making money off their labor. It's a small community, here, so there's a bit less of a "catch and release" mentality than you'd find with, say, Project Gutenberg or the Internet Archive. Legally, you don't have to, but the courtesy undoubtedly goes a long way, anyway.
Beyond that, the only advice I would give (and it's not legal advice, lest Bar Association Ninjas attack while I sleep...) is that, while we do check the copyright status of the books, you should double-check it and keep records of everything. Should you get a Cease and Desist letter in the (e-)mail, "someone else said they checked," isn't going to make anybody go away. That's blood in the water, as far as they're going to be concerned.
Best of luck, Michael, and I'm sure we'd all like to get a peek at where the product's going, should you care to get involved in the community here.
