Apple has announced three significant changes to its iTunes Store at Macworld Expo, but the first is undoubtedly the biggest news: The music and video download service, which features more than 10 million songs, is finally going Digital Rights Management (DRM)-free.

Apple senior vice president of Worldwide Product Marketing Phil Schiller told the assembled throngs at Macworld Expo this morning that the service has sold six billion songs since going online in 2003. More than 75 million accounts with credit cards have been created thus far.

No More DRM By End of March

iTunes Plus is Appleâ¬"s DRM-free encoding for the iTunes Store; music is encoded using the Advanced Audio Codec format (AAC) at 256Kbps. Beginning today, 8 million of the iTunes Store's 10 million songs will be offered without DRM; the entire catalog is expected to go DRM-free by the end of the first calendar quarter of 2009.

Users who have already purchased music from the iTunes Store protected with Appleâ¬"s FairPlay DRM will be able to upgrade their entire library of previously-purchased songs, though an additional fee is required--30 cents per song.

New pricing structure

Since going online, the iTunes Store has retained one pricing model--99 cents per track, with many albums priced at $9.99. Thatâ¬"s changing in April, said Schiller--there will then be three pricing tiers: 99 cents, 69 cents, and $1.29. Schiller assured the crowd that more songs are going to be offered at 69 cents than at $1.29, however.

iTunes Wi-Fi Music Store goes 3G

The iTunes Music Store previously was limited to allowing purchases on the iPhone only over Wi-Fi; that restriction has been lifted, at least for iPhone 3G users, who can now purchase and download content to their iPhones over a 3G connection. That feature is being implemented today, and provides iPhone users with the same price and selection on the iPhone as they would find on iTunes on the Mac or PC.