Now, before you start worrying about a change in name for Xbox Live, don't. That part isn't changing like the Playstation Network did. However, Xbox Live and Windows 8 will be connected in a way we simply do not know about yet. It will be deep, perhaps deeper than signing into our Messenger on our 360s.
Meanwhile, what will be changing is the naming for Live Messenger, photos, and email. Windows Live Photo Gallery shall simply be named Photos. Windows Live Mail is just Mail. Windows Live Messenger is just Messenger. And your Windows Live account will be renamed to Microsoft Account.
This might serve to be confusing for some since the Xbox Live accounts are referred to as Live Accounts. Don't worry too much, you still have some time to get used to it.