I was wrong when I wrote part of my article "A First Look at the VS2008 ReportViewer." Actually, I was mislead and believed what I was told about Visual Studio 2008 SP1 and SQL Server 2008 (Katmai) RTM. Apparently, the Katmai report processor was not incorporated into the ReportViewer (or as they now call it the "MicrosoftReportViewer") control during SP1. although it might look like Microsoft had upgraded the ReportViewer, it hasn'tonly a few bug fixes were applied. This means that the RDL generated by the newly released Katmai RDL code generators is NOT compatible with the Visual Studio 2008 SP1 version of the ReportViewer control. This means you can't take that set of reports you've generated with the new Katmai BI tools and import them into VS 2008 like you could take Yukon reports and import them into VS 2005 BI tools.
The article continues at