Siva's blog

Microsoft has announced the releasing period of Windows 8.
After the grant release of Windows 7 on October 22,2009, It had a great sales and impact in Compatability , security and faster than its previous version Windows Vista and Windows XP. According to NASA(Link) , it had also worked with other agencies for Microsoft to enhance Security.
Windows 7 is already sold twice as many as any other Windows product in one month.
In the meanwhile, Microsoft announced the Time frame for the release of Windows 8 in 2012. However because of the release of Windows 7 updates and Service Pack, i believe it could be delayed about another one year.

WIndows 8 Video http://vimeo.com/4255076
Note: Microsoft has a plan to release Windows server 2008 and Microsoft Office 2010 in upcoming years.