Gannett (NYSE: GCI) flagship USA Today is the latest paper to be sold through Amazon’s Kindle. The top-selling U.S. paper has yet to show up is now available at the Kindle Store but Amazon told Kindle subscribers on Christmas morning that they’ll be able to download the Dec. 26 edition for free. USA Today, which doesn’t publish on holidays, only offers weekday editions so the first issue for sale will be Dec. 29.  We’re checking on the subscription and single-issue prices. Single Kindle copies tend to go for 75 cents while monthly costs vary: the New York Times, published daily, is $13.99 a month, while the Wall Street Journal (six days) and the Washington Post (daily) run $9.99. Publishers get the bulk of the revenue share with Amazon (NSDQ: AMZN). Update: a monthly subscription to USAT is $11.99.

Often requested by Kindle users, USAT is only the 21st U.S. paper and the 28th paper overall to show up in the device store. Some publishers, including the NYT, have talked about their surprise at the service’s success but it’s hard to gauge just how meaningful that it. Amazon also has received considerable publicity from the likes of Martha Stewart raving about reading the Wall Street Journal on her Kindle (no ink to rub off) and others who talk about substituting print editions for Kindle subscriptions. (I don’t subscribe to any Kindle newspaper editions, preferring to keep my print subscriptions and download single issues while traveling.)

Kindle launched in November 2007 in time for the holidays but what should have been a breakout season for sales this year has been hampered by recurring supply problems credited, in part, to a popularity boost from an endorsement by Oprah Winfrey and a discount through her show. New models at $359 are currently out of stock at Amazon, with shipping estimated in 8-10 weeks; refurbished models are available sporadically. Amazon is encouraging would-be owners to sign up now to get a place in line when delivery resumes.

The company doesn’t release the actual number of units sold or the volume of Kindle content sales. External estimates of Kindle sales vary wildly from several hundred thousand to a million. On the content side, the percentage of revenue contribution is minimal overall. Brian Murray, CEO of HarperCollins Publishers Worldwide, said in the NYT earlier this week that the Kindle sales of The Story of Edgar Sawtelle, one of Winfrey’s book club titles, represent 20 percent of total Amazon sales for the book, an intriguing number but one that offers little context as to how the Kindle fits in to the big picture on sales.

Disclosure: paidContent.org has been available through the Kindle Store since launch.

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