In a number of publications (including the Wall Street Journal) it has been reported that Amazon will no longer offer small-press books for sale on their web site that are not printed through their POD publisher. Once the 'in-stock' supply has been sold, the 'buy button' will be removed from the listing. A statement that the book is available off-site will replace the button. This has already happened to a number of small presses causing a great deal of concern to publishers and authors.
From PW Daily:
Amazon to Force POD Publishers to Use BookSurge
by Jim Milliot
BookSurge, Amazon’s print-on-demand subsidiary, is making an offer that most publishers would like to refuse, but don’t feel they can. According to talks with several pod houses, BookSurge has told them that unless their titles are printed by BookSurge, the buy buttons on Amazon for their titles will be disabled. A detailed explanation of how the new program was explained to her is provided by BookLocker.com co-owner Angela Hoy on her writersweekly.com blog.