Jeremy Likness has published another quickstart which this time is about creating a
MEF "part" in
Silverlight.
Source: MEFContrib
The purpose of this quick start is to familiarize you with the Managed Extensibility Framework by composing a "part" in Silverlight.
Getting started with MEF is easy, once you understand the concept of parts. Because the purpose of this quick star is to get you up and running quickly, we'll start with a brief explanation and dive deeper in other tutorials. A part contains a contract, imports, and exports. One way to think of this is as an item in a store.