They're the first major publisher to sign with Bitlit, an app that lets you send a photo of your book's copyright page with your name inked on it in exchange for a deal on the ebook.
The Harpercollins pilot includes Neal Stephenson's classic Cryptonomicon, and will offer ebooks to print owners at $2-3.
BitLit Signs HarperCollins to eBook Bundling Pilot
(Thanks, Peter!)