Moonlight 2.0 brings the Silverlight 2 features like the embedded CLR along with support for an open-source toolkit, adaptive streaming support, and many more features. Some of the Silverlight 3 features that were integrated into Moonlight 2.0 include animation easing functions, support for custom media decoders, and support for a RGBA memory buffer to do its own low-level rendering. Other Silverlight 3 features that require more extensive modifications will then come with Moonlight 3.0.
More information surrounding the Moonlight 2.0 Beta 1 release is available in this blog post. Moonlight can be downloaded from the Mono Project.