Finally, a competitive move from Sony (NYSE: SNE) worth writing about, though it has its own caveats: it is opening up Sony Reader, its e-book reading device which is a competitor to Amazon (NSDQ: AMZN) Kindle, to other third party book stores. A new software update to the Reader will enable it to display books encoded in a format being adopted by several large publishers, meaning users can buy these ebooks from other stores, besides Sony’s own. The format, called Epub, means Reader can support books from supporting Epub publishers including Simon & Schuster, Penguin Group, HarperMedia, Hachette Book Group, HarperMedia and Harlequin. Epub is supported by International Digital Publishing Forum, the main e-book publishing trade group.

Reader is retailed for $300 device, while Kindle is for $359. Amazon’s bookstore has about 140,000 ebooks, while Sony only has about 45,000. This move from Sony still may not move the needle for it: users don’t go to publishers’ sites to buy the ebooks…for most part it still happens at central hubs like Amazon, BN.com and others. Then there’s the issue of the gadget itself; which one is better and easier to use? Meanwhile, Amazon is still mum on sales numbers for Kindle..it didn’t say anything in its Q2 earnings call earlier today.

In related news, the Reader has finally crossed the pond and launching in UK in September.