The images of Microsoft account has been leaked which shows the login screen named as Microsoft account which previously was known as Windows Live ID.
The images posted by NeoWin.net clearly shows the Windows Live ID now renamed to Microsoft account. The login page of Hotmail and SkyDrive now shows the Microsoft account instead of Windows Live.
There are no more news about from where these images were taken. But, we can assume that this Microsoft account branding would take effect from the Release Preview scheduled for June 1st lauch or maybe in final version of Windows 8.
Microsoft previously announced the Windows Live accounts would now be renamed to Microsoft accounts for Windows 8, Windows Phone and web users.
source:windows8core & neowin