Silverlight 3.0 has been released at https://www.microsoft.com/silverlight/resources/install.aspx.
It is an RTW version meaning Released to Web. The version number is Silverlight 3 RTW (3.0.40624.0).
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