How to Sign up for and Create a Microsoft Account
Microsoft account is the new name for what used to be called a "Windows Live ID." Your Microsoft account is the combination of an email address and a password that you use to sign in to Windows 8 or services like Hotmail, Messenger/Skype, OneDrive, Windows Phone, Xbox LIVE, Zune, Office Live, and Outlook.com. If you use an email address and password to sign in to these or other services, you already have a Microsoft account—but you can also sign up for a new one at any time.
Over time, all Microsoft services will be switching from the old name to the new one. You might continue to see mentions of "Windows Live ID" instead of "Microsoft account" for a while—for example, on xbox.com...