Terry Myerson, the Microsoft executive VP who is in charge of the software firm's operating systems, reportedly told employees on Thursday that the Windows Store and Windows Phone Store will be merged into one app store. The store will be available with the next version of Windows Phone 8.1 and a special update planned for Windows 8.1. Both updates should be out by next Spring. No comments were made as to how the unified store would work or what it might look like.
Another one of the questions not answered for now is whether this will mean that Windows Phone apps will work on larger screened Windows devices. Microsoft might borrow a page from Apple and allow apps for larger screened devices to run on those devices only, while Windows Phone apps run on handsets and are scaled up to run on devices like tablets.
source: TheVerge via SlashGear