MoqaLate is a free Mocking Framework for Windows Phone and is available for download from CodePlex.
MoqaLate is currently in Alpha, but is usable now.
MoqaLate generates mocks from any interfaces that it finds in your Windows Phone Project and copies them into your Windows Phone test project.
MoqaLate is available now on NuGet
PM> Install-Package MoqaLate
Know more about MoqaLate – Mocking Framework for Windows Phone. Here