Rumors swirled today that Amazon (AMZN) could revoke the buy buttons for books by Simon & Schuster, HarperCollins, Penguin, or Hachette if the major publishers can’t strike an eBook deal with the online bookseller.

Neither Amazon nor the publishers went on the record about the eBook pricing debate. However, the New York Times has spoken with unnamed publishing executives about the terms of the eBook deal–noting that major publishers are “reluctant” to strike this kind of deal: “Amazon has agreed in principle that the major publishers would be able to set prices in its Kindle store as well. But it is also demanding that they lock into three-year contracts and guarantee that no other competitor will get lower prices or better terms.”

Around the Internet, various commentators weighed in. eBookNewser noted that “it’s a war out there,” also reporting on Amazon’s quiet launch of a Kindle App for the Mac.

Business Week said the Amazon deadline for dealmaking will be “no later than the April 3.”

Fast Company speculated about news that venture capitalist John Doerr has stepped down from the Amazon board.

Finally, if you want to monitor buy buttons from those four publishers, we have a handy guide to double-checking after the jump.

Test the buy buttons for the “Agency Four” with these Amazon links…

Simon & Schuster: Courage and Consequence by Karl Rove
HarperCollins: Neon Angel by Cherie Currie and Tony O’Neill
Penguin: The Help by Kathryn Stockett
Abraham Lincoln: Vampire Hunter by Seth Grahame-Smith