I think it is more than iCloud. it is making your profile, your personalization and your content roaming. In case of iCloud, it is only the content if i am not wrong.
MobileMe has been doing settings and contact and such for a while now. It's buggy, mind you, but all of that functionality is going to iCloud.
You buy a new iPhone, login to iCloud, and it pulls all your settings over, configures your mail client, calendar, installs your apps, and downloads your music. You add a contact on your phone, it goes to your MacBook and iPad, etc.
You buy a new iPhone, login to iCloud, and it pulls all your settings over, configures your mail client, calendar, installs your apps, and downloads your music. You add a contact on your phone, it goes to your MacBook and iPad, etc.