Less than two weeks after Barnes & Noble's launch of the competing Nook Amazon.com has responded with a major shakeup to its Kindle lineup.

Amazon's changes include abandoning the Kindle 2, dropping the price of the new international edition from $279 to $259, and introducing a new Kindle for PC application as part of the launch of Microsoft's Windows 7 operating system.

As far as anyone knows, though, Amazon will still continue to sell its high-end model, the widescreen DX, priced at $489.

Based on historical trends in the still emerging e-reader market, the price drop on the international Kindle didn't come as a huge shocker.

But Amazon's seeming abrupt move to dump Kindle 2 could indicate that Amazon is feeling more pain from B&N's Nook than many people would have anticipated.

Due out in November, the Nook carries the same $259 price point as the newly re-priced international Kindle.

Although some argue that even $250 is too high, the Nook has been widely hailed as offering the kinds of capabilities that could kill off the Kindle 2, including a color display, Wi-Fi, a replaceable battery, and more books, just for starters. But isn't it kind of amazing just how fast that happened?