Apple has officially launched on Monday its new iTunes Match service, but in the US only.

In case you haven’t read about the service before, users can now subscribe to the $25/year service to have 25,000 songs from your library stored over the clouds.
Once your library is safely stored, you’ll be able to access it using any iOS powered device.

The tracks in your library that are already existing in the Apple’s iTunes music store, will not be uploaded from your library and when requested, they’ll be streamed back to you from Apple’s master copy at 256kbps. Therefore if your tracks were in a poorer bitrate, you’ll automatically gain in sound quality.

This means that if you are using the iTunes Match service you don’t need to have a and iPhone or iPod touch with a huge memory since all your tracks will be stored on the Apple Servers.
On the negative side though, you’ll always need to have an internet connection to access your library.

The service is for the time being available only in the US but we can expect to see it coming soon in more countries, licensing permitting.

To make use of iTunes Match, download iTunes 10.5.1 from your software update.