Link: Visual Studio Add-in: Portable Library Tools CTP

The Portable Library Tools Visual Studio add-in may be interesting if you’re writing applications that run on multiple .NET platforms.  It allows you to create libraries that run on a variety of .NET platforms (.NET, Silverlight, Windows Phone, Xbox 360) without recompilation.

Check out this blogpost by the BCL (Base Class Library) team to find out all the details.