According to this article from Neowin, Microsoft CEO Steve Ballmer has gone on record and told an audience in Japan that the next version of its Windows operating system will be released next year.
Furthermore, "Windows 8" was mentioned by name during Ballmer's speech, made at Microsoft's developers forum in Tokyo. Specifically Ballmer said, "As we progress through the year, you ought to expect to hear a lot about Windows 8. Windows 8 slates, tablets, PCs, a variety of different form factors."
Ballmer also revealed the company's plans for Windows Phone 7:
Ballmer also hyped up the upcoming Windows Phone 7 announcements that are scheduled to be revealed on Tuesday, saying, " ... that information will be forthcoming, including some of the particulars about who is going to be building Windows Phones, and which carriers will be offering them here in Japan."
You can read the full article here.