Universal Music Group, Sony BMG, Warner Music Group and EMI, along with thousands of independent labels, have made their music available through the format, which features audio quality "virtually indistinguishable from the original recordings," Apple said in a release.

iTunes customers can choose to download their favorite songs from the catalog directly onto their iPhone 3G over their 3G network just as they do with Wi-Fi for the same price as downloading to their computer, the company added.

"We are thrilled to be able to offer our iTunes customers DRM-free iTunes Plus songs in high-quality audio and our iPhone 3G customers the ability to download music from iTunes anytime, anywhere over their 3G network at the same price as downloading to your computer or via Wi-Fi," Steve Jobs, Apple's CEO, said in a statement. "And in April, based on what the music labels charge Apple, songs on iTunes will be available at one of three price points -- 69 cents, 99 cents and $1.29 -- with many more songs priced at 69 cents than $1.29."