Read original post at Jeff Handley's Blog
On September 1, 2011, Silverlight 5 RC was released. As always, RIA Services is included in the Tools for Silverlight, and that release included our V1.0 SP2 RC build. And also as always, we published a standalone installer for RIA Services. You can find it on the download center. The silverlight.net/getstarted/riaservices page will get updated soon to include the link to this build.
Jeff Handley