Book publisher Macmillan and Amazon settled their differences over the weekend over pricing, setting the tone for future e-books sold online.

Lass reading from Amazon Kindle - image from Amazon web siteMacmillan books started re-appearing on amazon.com over the weekend. Macmillan had wanted Amazon to allow it to price e-books in a similar way proposed by Apple with its iPad.

Amazon had pushed for best sellers to be sold online at $9.99 but the book publishers fear for margins with pricing at that level.

Apple's iPad and the associated publishing pricing model threatens Amazon's attempt to achieve hegemony and make its Kindle e-reader the standard.

Last week Hachette said that it too wanted to follow the Apple trail. The Apple trail, on the face of it, isn't brilliant for book publishers either. Apple gets 30 percent of the price of an e-book per title.

It also, no doubt, makes a heap from sales of the iPad gizmo and in usual Apple style buys the components low and sells high.

Google is waiting in the wings to make its own foray into the book publishing market too.