Microsoft has posted the SQL Server 2008 R2 August CTP bits for anyone that wants to see what this update has to offer. There are many great changes for SSRS coming in this release, including an all new Report Manager interface, Maps as a report item like graphs and charts and the best of all an AJAX enabled ReportViewer control! The ReportViewer control is not available for use in Visual Studio yet, but will be in the next beta of Visual Studio 2010 that gets released. Report Builder 3.0 is also available as a separate download (see links below).
The new ReportViewer control included in Report Manager will make this a must install upgrade as soon as it comes out in 2010!
For those that are also participating in the Office 2010 beta you can get the Gemini CTP as well, but Office 2010 is required since it plugs into Excel 2010. Gemini is also going to be part of SQL Server 2008 R2 when it comes out and is a self service Analysis Services technology that will work on the client desktop.