Windows 8 becomes officially available on Friday, but the Windows Store made its official debut on Thursday, opening online in 231 markets worldwide in 109 languages.

The Windows Store offers an impressive amount of software for download — Microsoft Windows division president Steven Sinofsky said at a Microsoft event on Thursday that there are more apps available at launch than any app store in history.

According to Wes Miller, an analyst with Directions on Microsoft, there were 7,873 Windows 8 “Modern” apps available in the store worldwide as of Wednesday, and 4,516 in the U.S. Windows Store. He added that of those nearly 8,000 apps worldwide, 88% of them are free. In the U.S. version of the Windows Store, 83% (3,749) of the apps are free.

Among those apps, so far we’ve seen Skype for Windows 8 (that we favorably reviewed), Netflix, which we think “looks great and provides easy access to new releases, recommendations and genres,” and the ubiquitous Angry Birds, one of the first games to be available at the Windows Store.