Metallica drummer Lars Ulrich was once the poster child for the record industry's opposition to digital music technologies, particularly those that allowed users to download free music from the likes of the former Napster.

Today, with both the illegal peer-to-peer (P2P) file-sharing services Napster spawned and Apple's legal download store iTunes thriving, Metallica joined the digital music fray, licensing its entire back catalog to iTunes.

"From the 'It's about f***ing time!' file, comes this," the band said in announcing the move. "Over the last year or so, we have seen an ever-growing number of Metallica fans using online sites like iTunes to get their music. So...we are now offering fans the opportunity to obtain our songs individually."

Metallica's move to digital sales, and a move by Detroit rocker Bob Seger earlier this month, leaves only a few holdouts, most notably the Beatles, Led Zeppelin, and Radiohead. The Beatles and its Apple Corps record company have engaged in a long standoff with Apple over the use of the apple logo and Apple's ability to sell music. A British court ruled in favor of Apple in that dispute in May.

To bolster its late entry in the digital music game, Metallica said it was adding previously unreleased live tracks on to each of the first four albums, Kill 'Em All, Ride the Lightning, Master of Puppets, and ...And Justice For All, for sale in iTunes.

Metallica's catalog is only available in iTunes in the US and Canada, however.

"This is unfortunately due to the fact that our record company overseas doesn't seem to want to play ball with us on this at the moment," the band said. "Hopefully this will get sorted out ASAFP, but we didn't want our fans in North America to have to wait any longer while our overseas record company tries to get their sh** together!"

Giving its fans the chance to buy individual songs had long been a point of contention for Metallica, which was concerned about moving away from the traditional album format. When iTunes launched in 2003, the band explained its absence from the iTunes catalog with a statement that it "would rather not contribute to the demise of the album format."

Metallica placed itself at the center of the controversy surrounding the dawn of digital music in 2000, when Ulrich appeared at a Redwood City, California, courthouse bearing a list of the names of tens of thousands of Napster users.

The move drew the ire of many Napster users and digital rights advocates, and was the subject of a series of online parodies by the Web site Camp Chaos.