The Windows Phone Store (previously Windows Phone Marketplace) is a digital distribution platform that allows users to browse and install applications that have been developed by third parties. The UI is presented in a very "Metro UI" way using a panoramic view where the user can browse categories and titles, see featured items, and get details with ratings, reviews, screenshots, and pricing information.
To submit and manage apps on Windows Phone Dev Center, you first have to register and become a member using a Microsoft account (formerly known as Windows Live ID). When registering, you will be asked to pay an annual Developer Center subscription fee of $99 plus any applicable tax. In exchange, you'll get to submit unlimited paid apps to Windows Phone Store (you can also submit up to 100 free apps). The publishing process is simple and straightforward: you have to provide the app details (name, description, screenshots, and so on) and then submit the XAP file packaged with Visual Studio. You must package and prepare your app before you can upload it to the store; the packaging process starts when you create a Windows Store project or item based on a template (refer to the online documentation at http://msdn.microsoft.com/en-us/library/windows/apps/br230260.aspx for a complete overview of the packaging process).
Note
The verification process is pretty fast, but you need a couple of days to complete the registration process if you are registering as a company.
In order to reduce the duration of the review, you can screen your app locally using the Windows Application Certification Kit (WACK) tool available in the Windows Phone SDK. It reduces the approval cycle by giving you a way to screen your app locally for issues before you even submit it to the Windows Store.