We’ve been hearing about Windows 8 for months, and today we can finally tell you it’s got a smart tile-based user interface, robust developer options and what is essentially a complete revamp of Windows 7 to bring Microsoft’s new OS into the mobile era.

Microsoft unveiled Windows 8 during the keynote at its BUILD developer conference Tuesday morning. Executives showed off the operating system’s versatility on a variety of mobile and desktop platforms, pointing out features like cloud-based photo sharing, streamlined contact management and the Metro UI overhaul. The OS is Microsoft’s first earnest push into the tablet space and it looks, at first glance, anyway, like it’s a true competitor to mobile operating systems like Android and iOS.

You can get access to a developer preview release of Windows 8, with or without development tools, beginning at 8 p.m. PST. The Windows app store will not be active in the preview release (which is not to be confused with a beta release of Windows 8), but the release does include a number of sample/SDK applications.

“I think Microsoft will really need to find a way to drive adoption of Win8 as fast as possible to
encourage the developer community to create these new-style apps,” Rendle said. The fact that the software is available as a public preview should help with that fact.

No date for a Beta launch of Windows 8 has been announced.

“We’re going to be driven by the quality, not by a date,” Sinofsky said.

Why code for Windows 8? Besides the robust developing options, Microsoft estimates that 400 million people will eventually adopt the Windows 8 ecosystem.

“Microsoft has made a significant investment to entice existing developers to build for the Windows 8 platform,” Blankenship said. “I can’t wait to get my hands on the Developer Preview build tonight!”

Windows 8 Re-Imagines the Windows Experience