This is true, genuine, official address is http://www.mono-project.com/Moonlight
The following is a page introduction
A page to track the varous projects that will make up the mono-based implementation of Silverlight.
Silverlight 1.1(Http://silverlight.net)Is a new development technology for the Web created by Microsoft Based on the CLR that augments it with a 2D retained graphics system and media playback engine and ships a subset of the standard. Net libraries.
Building an Open Source implementation on top of Mono is an obvious choice as mono has most of the technologies required to implement it but is missing a few components. in this page we will track the work required and the design decisions involved in creating an open source version of it.
Moonlight is the temporary name for the project.
Now you have a reason to focus on this new technology !!!