Developers in 120 countries around the world can now register for and submit applications to the Windows Store. Registering costs $99 a year for corporations, $49 a year for individuals, and is free for a year for MSDN and DreamSpark members.

Some developers have already had access to the store, and at the time of writing there are 1033 apps available; mostly free, but a few paid.

Apps will be on sale in 231 different markets, with the full list available here. Seventy-five of the markets will take payments in their local currency; the rest will be paid in euros or US dollars.

With Visual Studio Express available to download and time-limited Windows 8 RTM evaluation copies available to anyone, developers now have everything they need to start producing Metro-style applications. Windows 8's Metro environment needs a killer application: now the door is open.