In advance of Barnes & Noble's Nook Color unveiling tomorrow, Amazon is trying to capture a bit of the e-reader news today with a short release about how sales of the Kindle are roaring ahead. "It's still October and we've already sold more Kindle devices since launch than we did during the entire fourth quarter of last year--astonishing because the fourth quarter is the busiest time of year on Amazon," said Steve Kessel, senior vice president, Amazon Kindle.

Amazon says Kindle best-sellers are outselling bestselling hardcovers and paperbacks.

As is fairly typical Amazon didn't give any specific sales figures, but it did reiterate that Kindle book sales continue to overtake print on Amazon.com, "even while print book sales continue to grow." The company says that during the past 30 days its customers purchased more Kindle books than print books--hardcover and paperback combined--for the best-selling books on Amazon.com.

Kessel said that, "For the top-10 bestselling books on Amazon.com, customers are choosing Kindle books over hardcover and paperback books combined at a rate of greater than 2 to 1. Kindle books are also outselling print books for the top 25, 100, and 1,000 best sellers--it's across the board."

Tech analysts have been waiting for Amazon to say how many Kindle e-readers it's sold, but don't expect that any time soon. Amazon considers it a competitive advantage not to reveal specific numbers, and its Kindle business isn't large enough to be broken out in its annual report. We're not sure what to make of the "even while print book sales continue to grow" mention, but it suggests that Amazon is implying that it continues to gain market share across the board.