Apple has today released iTunes 10.5.1 with support for its new iTunes Match service. The update should be available now for all either via Software Update or through the iTunes download page.

Apple has also announced that the iTunes Match service is going live today.

Although some are seeing a notice that the service is still ‘in beta’, it appears to disappear once you have updated iTunes. iTunes Match is a service that will allow you to use any of your computers with iTunes installed to match your library with Apple’s music store.

If your song is on the store already, it is instantly available for download and playback almost anywhere, including other computers or your iPhone, iPod or iPad devices. Another cool aspect is that if your song is of lower quality, Apple will upgrade it to a 256Kbps AAC DRM-free copy.

If your song does not exist in Apple’s store, then it will automatically be uploaded to the cloud, allowing you to access it anywhere.

The service runs $24.99 a year and includes unlimited song storage and playback. This does not affect your iCloud storage. At the moment, iTunes Match is available in the US only.

At the moment it appears as if the service is having some difficulty, as we are receiving an error when we try to begin the matching process and some are seeing ‘over capacity’ messages.

Have you signed up for iTunes Match, if so, how is the process going for you?