Apple today announced that it’s sold more than 5 billion songs from its iTunes music store, an exclamation point for the company that emerged as the nation’s top music retailer when it overtook Wal-Mart this year.

The Cupertino, California-based iPod makers also announced that iTunes customers have made the free application the most popular online movie store, renting and buying more than 50,000 movies per day.

“The iTunes Store is the world’s most popular online music, TV and movie store with a catalog of over eight million songs, over 20,000 TV episodes and over 2,000 films including over 350 in stunning high definition video,” Apple officials say. “With Apple’s legendary ease of use, pioneering features such as iTunes Movie Rentals, integrated podcasting support, iMix playlist sharing, the ability to turn previously purchased tracks into complete albums at a reduced price, and seamless integration with iPod andiPhone, the iTunes Store is the best way for Mac and PC users to legally discover, purchase and download music and video online.”

According to The New York Times, “Wal-Mart was the largest music retailer in the country last year, so musicians (and their labels) are eager to maintain good relationships, appearing in the special concerts for the chain, which are also open to the public.”

The Times reported last week that Wal-Mart is cutting exclusive deals with major artists in a play to improve traffic to its stores and online operations.

But The Wall Street Journal has a little different picture of what’s really going on. Rock band AC/DC is about to announce a partnership with Wal-Mart in which it will sell its new album only in the largest retailer’s stores. The paper writes, “The AC/DC deal, however, comes at a time when the retail giant -- the largest seller of compact discs in the nation – is signaling it may rock the music world by stocking fewer CDs.”

Both papers say that the deal will hurt music labels that count on CD sales, but neither shows the extent to which Wal-Mart is becoming the unlikely largest competitor to iTunes.

In making its announcement, Apple gave a nod to the major motion picture studios it’s doing business with in its growing movie segment, including 20th Century Fox, The Walt Disney Studios, Warner Bros., Paramount, Universal Studios Home Entertainment, Sony Pictures Entertainment, Metro-Goldwyn-Mayer, Lionsgate and New Line Cinema.

“Users can rent movies and watch them on their Macs or PCs, all current generation iPods, iPhone and on a widescreen TV with Apple TV,” officials from the company said. “iTunes Store customers can also purchase new movie releases from major film studios and premier independent studios on the same day as their DVD release.”