Microsoft's Windows Store -- the built-in app store for Windows 8 and Windows RT -- is open to all developers in 120 markets, as of September 11.

Of these 120 markets, 82 are newly supported, as of today, according to a new post on the "Windows Store for Developers" blog. (Here's a list of the markets now supported.)

Read more at source:
Microsoft's Windows Store now open to all developers in 120 markets | ZDNet

See also:
How to Install Metro Apps from Windows 8 Store