Radiohead's back catalog became available for sale via Apple's iTunes Music Store this morning (June 3) in DRM-free files, removing the band from the ever-dwindling list of major holdouts from the digital download service.

The band previously had a handful of songs on iTunes that were included on various soundtracks or compilations, and earlier this year, Radiohead's new album, "In Rainbows," was made available there.

But only today have the band's first six studio albums, and a brand new "Best Of" release, gone live. Radiohead had been holding out because of its desire for fans to buy the albums in complete form, rather than as individual tracks.

Sources say iTunes always had the option of selling Radiohead's back catalog in album-bundled form, but did not do so, in keeping with the fact that the overwhelming majority of artists sell their music as individual track downloads on the service.

Radiohead's decision to change its digital sales policy looks to have been a smart one from a financial standpoint. "In Rainbows" has sold 106,000 of its 526,000 U.S. copies digitally, according to Nielsen SoundScan. Individual tracks from the album have sold 178,000 copies.

Last September, U.K. retailer 7digital scored a coup when it added Radiohead album downloads to its service, but not individual tracks.

The Beatles, Garth Brooks and AC/DC are now the last superstar acts without a presence on iTunes.

Additional reporting by Lars Brandle, London.