Microsoft hosted a special event in San Francisco yesterday to discuss details about its upcoming application store for Windows. The company shared details on everything from registration fees to the approval process, revenue model, as well as advertisements and in-app purchases. It also confirmed that a beta of its app store, named the Windows Store, will launch as part of the Windows 8 beta in late February.

Built using HTML5 and JavaScript, the Windows Store will feature the same touch-friendly UI that’s familiar to Windows Phone 7 users, except it will be full screen and available on your computer. As Microsoft indicated earlier, it's intended to be the single source of Metro-style apps to allow better discoverability and facilitate in-app purchases. The store will offer support for both x86 and ARM-based hardware.

During the initial trial period, the Windows Store will feature free apps only and app submissions will be by invitation. However, once Microsoft opens submissions to the wider developer community, they will be able to price their creations from  between $1.49 to $999.99 or offer them for free. Microsoft will take a 30% cut on sales, but that will drop to 20% as soon an app makes $25,000 from sales and in-app purchases.

That's a better deal than what Apple or Google offer with their respective app stores, which charge a 30% commission indefinitely. Also unlike its rivals, Microsoft will allow time-based and feature-based trial versions of apps in its store, which can be upgraded later to the full version if the developer supports it.

In order to submit apps individual users will need to pay a one-time registration fee of $49 while companies are charged $99. Windows 8 will be a curated platform, at least as far as Metro apps are concerned, so developers will need to go through the approval process. Microsoft has already laid out its criteria for app approval here. There will be status updates throughout the entire process, and developers whose apps are rejected will be given feedback on what changes they'll need to make to get approved.

During the presentation, Microsoft’s VP of Windows Web Services Antoine Leblond emphasized the potential reach of the Windows Store, pointing out that some 400 million x86-based PCs are expected to ship over the next 12 months. That's on top of the 1.25 billion Windows PCs already on the planet.

The software giant will make the Windows Store and the apps in it available in more than 100 languages with availability in 231 markets around the world. To encourage developers to get working, Microsoft will be running a competition for eight winning apps to be featured on the Windows Store when it opens.

It should be noted that traditional desktop applications on Windows 8 will continue to be available through the usual channels, such as the developer's website, a downloads portal, physical media and so on.