The unholy union of Windows and Mac shall be consummated with the appearance of Windows 7 on an iPad.

Onlive, the company that made cloud computing cool with their game streaming service, are bringing virtual desktop streaming to the iPad. They announced that their OnLive Desktop app will be available on the iPad on January 12.

The OnLive Desktop app builds upon their previous experience with streaming PC games to stream a Windows 7 desktop to devices. The iPad being the first device to receive the service. With the app, iPads will have access to all the business applications that Windows users enjoy such as Microsoft Word, Excel and PowerPoint.

The app also brings with it a full on-screen Windows keyboard and handwriting recognition. This will bring the full desktop experience to the iPad with all the viewing and editing tools needed to work on complex documents.

“OnLive Desktop is the first app to deliver a no-compromise, media-rich Windows desktop experience to iPad, opening up powerful new possibilities for consumers and businesses,” Steve Perlman, OnLive Founder and CEO, said. “iPad users will now be able to simply and securely view and edit cloud-hosted documents with full-featured Windows desktop applications like Microsoft Office, just as if they were using a local high-performance PC. Multi-touch gestures respond instantly and smoothly, while HD videos, animations and PC video games—never before usable on a remote desktop—play seamlessly.”

There will be a free and pay for version of the desktop app available on the iPad app store. The free version launching on Thursday offers 2GB of cloud storage and as-available access to a cloud-based Windows 7 PC. In layman’s terms, it means that free users have to wait in line until a server is open for them to use. After all that line waiting though, users will be able to play around with a pre-populated Windows desktop featuring Word, Excel and Powerpoint.

The pay for version will come later, but will offer 50GB of cloud storage, priority access (less line waiting), full-featured web browsing, additional PC apps and other OnLive-unique features for $9.99 a month.

The OnLive Desktop app will also be coming soon to Android devices, PC, Mac and monitor/TV support through the company’s MicroConsole or Google TV.

Interested parties can sign up for their free account now.

Will you be using the OnLive Desktop app? Does Windows on an iPad seem amazing to you or just heresy? Let us know in the comments.