Silverlight version 3.0 has been released at Microsoft Website. It is an RTW version meaning Released to Web. The version number is Silverlight 3 RTW (3.0.40624.0).
http://www.microsoft.com/silverlight/resources/install.aspx.
Silverlight includes more than 50 new features. One of the most notable feature is offline mode which can be viewed out of the browser, 3D support, GPU acceleration and a lot more. Even with lot of huge features it is almost the same size as Sivlerlight 2.0.