Besides releasing the Windows 8 Developer Preview at the BUILD developer conference in September, Microsoft also announced an app store for Metro-style apps called  the Windows Store. However, the Windows Store can’t be accessed from within that pre-beta build of Microsoft’s upcoming tablet-friendly OS. This will change in February when the Redmond-based company releases the beta of Windows 8.

The software giant on Tuesday hosted a special Windows Store Preview event in San Francisco to shed some light on the app repository. First things first, the Windows Store is itself a HTML5- and JavaScript-based “Metro-style app taking advantage of the Metro-style design principles inspired in Windows 8.

Intended to be the only source of Metro-style apps, it will only contain free apps when it makes its debut as part of the Windows 8 beta in February. But once Windows 8 proper hits the market, developers will be able to sell apps priced anywhere between $1.49 and $999.99. Microsoft plans to reward quality by letting developers keep 80 percent of revenue after total revenue crosses $25,000, with the first $25,000 being “paid out at the industry standard 70 percent revenue share.”

Microsoft has also detailed the approval process: “The goals of the Windows Store app certification process are to ensure trusted, quality experiences for consumers while being as simple and transparent as possible for developers. Developers can test their app through the Windows App Certification Kit (ACK) [available now] and troubleshoot any technical issues before submitting to the Windows Store.”

“After submission, they will be able to use the Windows Store Dashboard to watch their app every step of the way. The Windows Store App Certification Requirements (http://msdn.microsoft.com/library/windows/apps) detail criteria for testing and certifying apps for the Windows Store.”

In a bid to stir up interest among developers, the company has announced a “First Apps Contest.” Open for submissions through Jan. 8, 2012, this contest will “select eight winning apps to be the very first apps in the Windows Store when it opens.” The winning developers will each receive a Samsung Windows Developer Preview PC, one year of Windows Azure and a two-year subscription to the Store.