(Reuters) – Microsoft Corp. (Nasdaq:MSFT – news) is releasing preview versions of its new Windows Vista operating system about once a month in an effort to get more customer feedback than usual ahead of next year’s launch, the company said on Tuesday. The world’s largest software maker also reiterated its plan to launch Vista in the second half of 2006, five years after the release of its current version, Windows XP. It is the longest gap ever between major launches of Microsoft’s core Windows product, the company’s cash cow which accounts for more than a quarter of its $40 billion in annual revenue. Read more