iTunes 10 for Windows: Access your complete iTunes music library at any time on all of your computers and iOS devices
iTunes Match stores your complete iTunes music library in iCloud—including songs you imported from CDs and songs that weren’t purchased in the iTunes Store—so all your songs are available on your computers and iOS devices at any time. With iTunes Match, you can download some or all of your music directly from iCloud on a total of up to 10 devices and computers.
When you subscribe to iTunes Match, iTunes sends information about the songs in your iTunes library to Apple. Songs that are available in the iTunes Store are added first to your iCloud library. If any songs in your iTunes library aren’t available in the iTunes Store, iTunes uploads only the songs that can’t be matched. This is a one-time process, though iTunes checks periodically to make sure your iCloud library is up to date.
iTunes Match is available for an annual subscription fee, and requires an Apple ID. If you don’t have an Apple ID, you can create one during setup.
To subscribe to iTunes Match:
-
If you haven’t signed in to the iTunes Store, sign in using your Apple ID.
-
In iTunes, choose Store > Turn On iTunes Match.
iTunes Match (below Store) is selected, and a new screen appears on the right.
-
Click the Subscribe button, and then follow the onscreen instructions.
The amount of time this takes can vary greatly, depending on the number of songs in your iTunes library. When setup is complete, an iCloud icon 
appears in iTunes next to Music (below Library).
To turn on iTunes Match on additional computers:
-
In iTunes, choose Store > Turn On iTunes Match.
iTunes Match (below Store) is selected, and a new screen appears on the right.
-
Click “Add this Computer.”
An iCloud icon appears in iTunes next to Music (below Library).
To turn on iTunes Match on your iPod touch, iPhone, or iPad:
-
On your device’s Home screen, tap Settings, and then tap Music.
-
Tap Turn On iTunes Match.
To download songs from your iCloud library to a computer:
-
In iTunes, select Music (below Library).
-
If a song is available for download, it has a Download button
next to it. To download the song, click the Download button. You can also play a song that’s available for downloading by double-clicking it. The song downloads as it plays.
To update the songs in your iCloud library:
iTunes checks periodically to make sure your iCloud library is up to date. You can also update your iCloud library at any time.
In iTunes, choose Store > Update iTunes Match.
Your iCloud library can store up to 25,000 songs. Songs purchased from the iTunes Store aren’t counted toward the limit.
Songs that are matched are stored in your iCloud library at iTunes Plus quality (256-kbps DRM-free AAC), regardless of the bit rate of the original files. Songs that are uploaded are stored at their original quality.
Files larger than 200 MB can’t be uploaded.
Only music videos purchased from the iTunes Store can be stored in your iCloud library.
If a playlist includes any items that aren’t songs, the playlist isn’t uploaded. Smart Playlist rules are uploaded, and are applied to the songs on the computer or device they’re downloaded to.
For information about the symbols used in iTunes Match, visit the iTunes Support site.