The always thoughtful Shawn Blanc has some thoughts on what Apple will do with iCloud. Essentially he says they will move MobileMe over, add dedicated storage for music and a place to sync 3rd party app data. All things that I believe are realistic, with one exception. Blanc believes Apple will only charge for the storage of music but give the rest away for free.
I don’t buy that. I think Apple is going to make the whole thing free. The services will be useless without Macs and iOS devices and will force users to buy those in to order to use it. I also believe that the online storage/streaming of music will only be music that you have purchased through iTunes, meaning that you have to buy a lot of music to make the most use of it.