Windows 8 is already running on 100,000 Apple Macintoshes, The VAR Guy learned today during Microsoft Worldwide Partner Conference 2012 (WPC12) in Toronto. The figure suggests Microsoft's operating system upgrade will find a niche (but strong) following on MacBooks, which are widely used by independent software developers (ISVs) and application writers that jump between Windows, Mac OS X and Linux.

How does The VAR Guy know the Windows 8 preview is already running on 100,000 Macs? Parallels CEO Birger Steen told him today at WPC12.

Parallels, as you may recall, develops virtualization software that allows Mac OS X and Windows to coexist seamlessly on Apple Mac hardware. The super-interesting twist: Parallels also allows Macintosh users to download and activate Windows 8, and Parallels has been tracking the Windows 8 downloads onto Macintosh systems, Steen -- himself a Microsoft veteran -- said.

Of course, Windows 8 is likely running on thousands of additional Macintoshes that lack Parallels' software.

Microsoft earlier today confirmed that Windows 8 will ship in October 2012. CEO Steve Ballmer compared Windows 8's launch to the birth of the PC in 1981 and Windows 95's arrival in 1995.

“This is an epic year,” said Ballmer. “The PC mainstreamed technology in 1981. Windows 95 made computers open and accessible to everyone. Windows 8 will kick off the most epic year in Microsoft’s history."

Hmmm... Ballmer is his usual upbeat, over-the-top self. Some critics allege interest in Windows 8 trails the build-up to Windows 7. But all of those users running Windows 8 on Mac hardware suggest that Microsoft has attracted the curiosity of developers and next-generation users.

Of course, Microsoft would prefer those Windows 8 users leverage Ultrabooks and other more traditional PC hardware. But hey, a software license is a software license -- and the Macintosh user base is a lucrative one...

Meanwhile, Parallels is building quite a business in the cloud market -- empowering cloud services providers and VARs to launch their own cloud services or white label third-party services. More details about that on The VAR Guy's sister site, Talkin' Cloud, soon.