Microsoft\u2019s senior vice president of its Windows Core Operating System Division, Brian Valentine, on Friday tendered his resignation and told the Redmond, Wash.-based software giant that he\u2019d be moving into an executive position with Web retailer Amazon.com, SeattleTimes.com reports. Valentine oversaw the development and launches of the firm\u2019s last three major operating system (OS) upgrades, and his announcement comes at a time when Microsoft\u2019s oft-delayed Windows Vista OS seems to be on the brink of release, according to SeattleTimes.com. Earlier this week, Microsoft released its Vista Release Candidate 1 (RC1) to millions of testers for input and feedback, and it said it will stick to the planned release schedule for Vista\u2019s final version of November for business users and January 2007 for consumers.Valentine was brought onto the Windows OS development team in the late 1990s by Microsoft Chief Executive Steve Ballmer to prepare Windows 2000 for its launch, according to SeattleTimes.com.Analysts suggest that Valentine\u2019s move may be a sign that a final version of Vista is indeed nearly ready for widespread release, as he seems to have left the firm on good terms, SeattleTimes.com reports.Valentine previously reported to Windows Core Operating System Division Co-Presidents Kevin Johnson and Jim Allchin. Jon DeVaan, who shared the SVP role for the division with Valentine for the past half-year, will take over complete management, according to SeattleTimes.com.Patty Smith, an Amazon spokeswoman, said Valentine will join the company as a senior vice president but did not provide further detail on what role he will play, according to SeattleTimes.com.Forty-six-year-old Valentine is a graduate of Eastern Washington University, SeattleTimes.com reports.Related Link:\n\nTesters: Microsoft Windows Vista RC1 Seems StableThis article is posted on our Microsoft Informer page. For more news on the Redmond, Wash.-based powerhouse, keep checking in.Check out our CIO News Alerts and Tech Informer pages for more updated news coverage.