It looks like the iTunes Match service might be getting closer to launch. AppAdvice noticed that the button magically appeared in the iOS 5 Music Apps settings today. Sure enough it appears in mine as well.
iTunes Match is designed to let you have music you did not purchase through iTunes available through Apple’s iCloud for a few of $24.99 a year. So, if you’ve ripped music from CDs or gotten it from other sources, the fee will basically allow you to have those songs stored in iCloud and then streamed to your devices. Unlike other Cloud music services, you won’t have to upload all of your music content to have it available for streaming. If you purchased it on iTunes or subscribe to the iTunes Match service you device will be able to play any song you’ve got in your library. You’ll supposedly only have to upload songs iTunes can’t match.
Looks like this may get switched on soon but it isn’t there yet.