On the heels of the news that Microsoft plans to create its own online music store, now the world's largest retailer says it has similar intentions - and that it plans to unveil the service yet this month.

The service would compete with a myriad of other digital services, such as Apple Computer's much-hyped iTunes service and one operated by Buy.com.

In the wake of Apple's success with iTunes, which was launched earlier this year and recently was made available for Windows users, Wal-Mart's launch will be the first of several planned launches of online music stores by some of the company's largest media and technology companies. It is unclear what Wal-Mart's pricing strategy will be for music downloads. Prices on existing services range from 79 cents to 99 cents per song. But Wal-Mart, which accounts for roughly 20 percent of U.S. music sales, typically sells music at a loss to attract customers to its stores.

This could get interesting. All the current players have offered similar pricing structures, but Wal-Mart doesn't play by anybody else's rules. As this excellent article by Charles Fishman points out, Wal-Mart likes to call the tune.

Wal-Mart wields its power for just one purpose: to bring the lowest possible prices to its customers. At Wal-Mart, that goal is never reached. The retailer has a clear policy for suppliers: On basic products that don't change, the price Wal-Mart will pay, and will charge shoppers, must drop year after year. But what almost no one outside the world of Wal-Mart and its 21,000 suppliers knows is the high cost of those low prices. Wal-Mart has the power to squeeze profit-killing concessions from vendors. To survive in the face of its pricing demands, makers of everything from bras to bicycles to blue jeans have had to lay off employees and close U.S. plants in favor of outsourcing products from overseas. [Emphasis added].

So, the questions become: what is Wal-Mart truly capable of offering (since their music selections have typically been predominently mainstream), and will everybody else end up having to match whatever Wal-Mart proposes in terms of pricing structure?

Note: The author wastes a fair amount of time blogging about a variety of subjects over at Walloworld, where this post originally appeared.