Apple has publicly released iTunes 10.5.1 and announced that iTunes Match is now live.

Coming just days after the developer release of iTunes 10.5.1 beta 3, the new version of iTunes allows users to access iTunes Match – a $24.99/year subscription service – for the first time.

iTunes Match enables iCloud storage of your entire iTunes library (all songs, even if ripped from CDs) for playback on any iOS-enabled device. Apple also offers to upgrade your music to high-quality 256kbps AAC files, even if the original files were of lower quality.

Once installed, users can sign up for the new service through the iTunes Music Store.