Ribbon was one of the highlighted features of Windows 7 which was unveiled at the PDC 2008. Looks like the ribbon features are coming to Vista also as Microsoft wants everyone to use it. In a session at PDC, Microsoft outlined Ribbon development and also urged developers to include it in their applications. Windows 7 will have the ribbon features in-built and Vista will get ribbon features through a redistribution package.
Img Credit: Neowin
Windows Ribbon for Vista will be available next year for use within applications too.