Microsoft plans to release a nearly final version of Windows 8 this summer that will give consumers and businesses their final chance to kick the tires on the redesigned operating system before it's released for sale, most likely later this year.

Windows group president Steven Sinofsky announced the Windows 8 Release Preview at a technology conference in Tokyo Tuesday. He said it would be freely available for download in June, but provided few other details. Sinofsky also Tweeted the news with a post that read, "Announce ... Windows 8 Preview first week of June."

Sinofsky's announcement of a Release Preview, or release candidate, as some are calling it, immediately sparked speculation that Microsoft may be preparing to ship a final version of Windows 8 to computer makers as soon as October, with Windows 8 devices on the market shortly thereafter.

[ Get expert guidance on Microsoft Windows 8. InformationWeek's Windows 8 Super Guide rounds up the key news, analysis, and reviews that you need. ]

The Windows 7 Release Candidate dropped in May 2009, and the final version of that OS was released in October 2009.

Microsoft last week for the first time revealed specifics about Windows 8 versions and features, confirming that the operating system will come in three, traditional desktop editions and a version built specifically for tablets that run chips based on ARM's reference design.

Windows 8, Windows 8 Pro, and Windows 8 Enterprise will run on traditional desktops and laptops, as well as ultrabooks. Windows 8 RT will run on tablets that use ARM-based chips manufactured by Qualcomm, Motorola, and Nvidia. Windows 8 RT will only be available as a preinstalled OS on tablets and other mobile devices. Those tablets will also come with a touch-optimized version of Office 15 preinstalled.

The Windows 8 lineup represents a streamlining of sorts by Microsoft. By comparison, Windows 7 was available in six editions, including Starter, Home Basic, Home Premium, Professional, Ultimate, and Enterprise. Microsoft did not release pricing details of the various Windows 8 versions.

Windows 8 marks Microsoft's most significant redesign of its franchise OS since Windows 95. The new OS gives users the option of ditching the familiar Windows Explorer interface in favor of the touch-based Metro UI, which first appeared on Windows Phone.

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