Who knew the way we read would spark such competition? The eReader war is underway!

Just weeks after Barnes & Noble launched the Wi-Fi version of its nook, as well as dropped prices on the 3G model, Amazon is reacting, not just with lower prices (that happened already), but with an enhanced new version of its popular Kindle. The online retailer just announced two new Kindle ereaders which can be ordered now and will begin shipping next month.

First up is the new Kindle, which promises an improved electronic-ink screen with 50 percent better contrast than its predecessor. It's also extra slim and lightweight at 8.7 ounces, but has kept the same 6-inch screen.

All these improvements come with no increase in cost: The new Kindle wil set you back $189, which is still $10 cheaper than the nook. The new Kindle includes free 3G wireless, for instant downloading of ebooks from virtually anywhere in the world (well, anywhere with a 3G wireless signal that is).  It also offers built-in Wi-Fi, and can hold up to 3,500 books.

Speaking of cheaper, Amazon also unveiled the new Kindle Wi-Fi. Like the 3G version, it's priced $10 below the Barnes & Noble counterpart. At $139, the Kindle Wi-Fi drops the 3G service as well as international coverage. Most of the other features are the same, including the battery life and storage capacity.  With this version, you'll need a Wi-Fi connection in order to download books, or surf web sites via the Kindle's new web kit-based web browser (the web browser is built into the 3G version too, of course).

Other features on both devices include Amazon's Whispersync technology, faster page turns, free sample chapters, the promise of books in 60 seconds, and a selection that includes more than 630,000 books, audiobooks, periodicals and blogs. If you need a few freebies, Amazon also offers 1.8 million free, out-of-copyright titles.

Amazon is still selling the Kindle DX, which has a larger screen, but no Wi-Fi. The new Kindle and Kindle Wi-Fi are available for pre-order now. Expect both devices to start shipping on August 27, 2010.

Where to Buy:

• Kindle Wi-Fi on Amazon.com
• Kindle 3G + Wi-Fi on Amazon.com
• Kindle DX on Amazon.com