Silverlight 2 Release Candidate 0 (Silverlight 2 RC0) is now available to developers for testing purposes and to help prepare your Silverlight 2 Beta 2 applications for the release of Silverlight 2. This release should not be used for launching Silverlight 2 applications for the general public

 

More details at

http://silverlight.net/GetStarted/sl2rc0.aspx