Finally, Microsoft has released all important tools for the first touch with Silverlight 3 (Runtime, Blend 3, SDK, Documentation and Tools for Visual Studio). SDK with client/server libraries is a pleasant surprise.
Silverlight 3 for Developers Runtime - http://go.microsoft.com/fwlink/?linkid=143433
Silverlight 3 Tools Beta 1 for Visual Studio 2008 SP1 - http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=11dc7151-dbd6-4e39-878f-5081863cbb5d
Silverlight 3 SDK Beta 1 - http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=d09b6ecf-9a45-4d99-b752-2a330a937bc4
Documentation - http://msdn.microsoft.com/en-us/library/cc838158(vs.96).aspx
Blend 3 Preview - http://www.microsoft.com/expression/try-it/blendpreview.aspx
Silverlight 3 for Developers Runtime
Silverlight 3 Tools Beta 1 for Visual Studio 2008 SP1
Silverlight 3 SDK Beta 1