Microsoft has just released the Silverlight 2.0 RC0. Unlike the Beta 2 release, Release Candidate 0 is intended for developers only. It could be used to ensure that current Beta 2 applications will be compatible with Silverlight 2 full version. Accoding to Scott Guthrie, a ship load of bugs have been fixed, blocks of code have been heavily optimized for performance, yet it also manages to cramp three more controls as bonus: ComboBox, ProgressBar and PasswordBox. More new controls, including TreeView , are expected to come out within the next few months.

Here are some important links:

Microsoft® Silverlight™ Tools for Visual Studio 2008 SP1 (RC0)

Microsoft Expression Blend 2 SP1 RC Preview

Breaking Changes Since Beta 2

Note that you'll need to uninstall previous Silverlight tools and runtimes in prior to installing new tools.