Today Apple released iTunes 10.5.1, whcih now lets you take advantage of the iTunes Match feature of iCloud. The service costs $25 per year and lets you store all of your music in iCloud. Your entire collection is conveniently available to you without having to store the whole collection on each deevice. When you subscribe to the service, it checks your iTunes Library against the iTunes Library of 20 million audio files. And for those in your collection that match their library, it adds those songs to your iCloud library.