Just ask!
A couple of people have expressed hesitation because they weren't promising to teach the preprint. There is no such requirement. If you're interested in seeing what we have so far, send mail and you'll get a copy. One person spoke of having an HCI course on the books that had never been taught, and there are no plans to teach it, but the person said he had a student who would like a do a senior project where the preprint would help with. It's been sent already!
If I get in a bind on the mechanics, I suppose I'll send copies first to people who think they might like to beta-test it in the summer. But unless the demand is very much greater than I'm guessing, I'll simply send a copy to everyone who asks for one.
If you want to assume I do this out of the goodness of my heart, feel free, but if you think a bit you'll see the self-interest as well. Getting copies out, and getting feedback, is very much to my advantage, long-term.
To send you a copy of the draft I need an address that FedEx can deal with, with mostly means that it can't be a PO Box. Home or office makes no difference to me. And they want a phone number. When I don't have one I make something up. Nobody has noticed yet, but if you don't mind, give me a phone number too.