I have put a copy of my book into the giant public-domain library that is BookCrossing. It's initially going out as a BookRay, which is a list of people who want to read it, kind of like a chain-letter - except that instead of sending money, you get to read books.
To get on the list you put your name down, PM me your address, and are added to a list. When it's your turn, the last person mails the book to you. And when you've read it, you mail it to the next person on the list.