Report Builder 3.0 RTM
The Feature Pack for Microsoft SQL Server 2008 R2 was released for download earlier this week, and includes PowerPivot for Excel 2010, as well as Report Builder 3.0!
The stand-alone download package for Report Builder 3.0 is available here: https://www.microsoft.com/downloads/details.aspx?FamilyID=d3173a87-7c0d-40cc-a408-3d1a43ae4e33
You can read about several of the new features and scenarios enabled with Report Builder 3.0 and RDL Version 2010, and take a look at the documentation overview for the latest version of Report Builder.
Enjoy and Happy Reporting!