At present my wife and I both have iphone's with a single MobileMe and iTunes account configured on both devices. This way we share the same contact list and calendars and music. Going forward, if I configure a single iCloud account on both devices will iMessage think both devices are the same person. i.e If I send a message from Messages on my phone, will it be able to use iMessage, or will it have to default to SMS because it treats her phone as me? Alternatively, is there a way we can have our own iCloud accounts, but setup synchronizing of our calendars/contacts etc between accounts, and share the same music?