1- Prism Library for WinRT (Windows Store Apps):
I have been waiting for the Prism implementation on WinRT for a long time. Prism for Silverlight and WPF has been a great reference for implementing loosely coupled and well designed (based on proven architectural patterns like SOC etc.) MVVM apps.
Just like with every new platform early adopters need architectural and design guidance to build applications based on best practices and proven design principles. Prism for WinRT (business apps) provides two libraries that offer proven design patterns such as MVVM (along with state management, validation of user input, navigation, data binding, commands, flyouts, settings and search) as well as the event aggregation pattern. These two libraries are available under Microsoft.Practices.Prism.StoreApps and Microsoft.Practices.Prism.PubSubEvents namespaces.
For more details, guidance and source download, click here.
2- Windows Store Business Apps using Prism
Patterns and Practices team has also published a detailed guide for building Windows Store business apps using PRISM for WinRT. The guide provides source code and documentation for a reference implementation of an AdventureWorks Shopper Product catalog and shopping cart. For more details and source code download please click here.
PS: This is available for XAML apps.