seems that, contrary to what appeared at first, yes there will be room for Open Source applications on the Windows Store , but not all.
According to The Register
in the future store software Windows 8 will accommodate any application with a license that has been approved by the OSI (Open-Source Initiative), and they are few, although not included the GPL . That is, contemplates OSI, Microsoft does not.
The reason would be because of a clause in the license terms of standard Windows applications store, which means basically that no application free can force another to comply with its license terms , which does happen with the GPL (although, as the restriction is raised, it should only affect the GPL 3).
Thus, there will be Open Source in the Windows Store, but only if the licenses are “compatible” with the business, so they will stay out of the store bigwigs many free software , as LibreOffice GIMP or, to cite two examples .