Silverlight 3 Beta was released at the MIX09 today and the developer beta is now available for download from the official Silverlight.net web site.
There is also a preview version of Expression Blend 3.0 at the official Microsoft Expression web site.
The download page has all the information and tools you need to get started including the SDK, Visual Studio Tools and so on.
INTERVIEW WITH SCOTT GUTHRIE
There is an interview available with Scott Guthrie on channel9in which he talks about the beta release of Silverlight 3.0 today at MIX09 and other new related technology .
IMPORTANT DEVELOPER NOTE (from the Silverlight web site):
Once you install the Silverlight 3 Beta Tools for Visual Studio, your development environment will be a Silverlight 3 Beta environment. Visual Studio 2008 SP1 does not support multi-targeting for Silverlight applications so you will be unable to develop Silverlight 2 applications once these tools are installed. We recommend that you install the Silverlight 3 Beta tools on a separate environment if you still need to have the ability to develop Silverlight 2 applications.
Ensure that you have either Visual Studio 2008 SP1 or Visual Web Developer Express 2008 SP1 installed as it is a prerequisite for the Silverlight 3 Beta Tools for Visual Studio. Below are the additional tools you’ll want to get started:
SILVERLIGHT 3.0 VIDEOS
There are also a whole bunch of new Silverlight 3 video’s available in the “Learn” section of the Silverlight.net web site. I haven’t watched them all yet but the ones I watched were from the one and only Mike Taulty, a must for developers.