As you probably know by now, Microsoft has recently released Service Pack 1 of Visual Studio.NET 2005. Since the Report Viewer controls are owned by the VS.NET team, it turned out that they have been updated also. Many bug fixes have been implemented. The new features include:

Report Viewer ASP.NET Control Enhancements

• Reset method to reset the control to its default values.

Both ASP.NET and Windows Forms versions

• ServerReport.Cookies property to pass cookies to the server (useful if the Report Server is configured for custom security).
• ServerReport.Headers property to pass custom HTTP headers to the server (useful if the Report Server is configured for custom security).  
• New (currently undocumented) IReportViewerMessages2 interface for localizing additional menu strings that were not covered by the original IReportViewerMessages interface.

Strangely, VS.NET 2005 SP1 doesn't update the product documentation (perhaps, the next edition of MSDN library will) so you need to rely on the online documentation.

How can you tell if you have the SP1 version of the controls? Once you install SP1 (don't interrupt the second part!!!), open Windows Explorer and navigate to C:\Program Files\Microsoft Visual Studio 8\ReportViewer. Right-click on one of the assemblies there (e.g. Microsoft.ReportViewer.WinForms.dll), choose Properties and flip to the Version tab. The file version should be 8.0.50727.762 and it should match the GAC version of the same assembly.