The Report Viewer Control available with Visual Studio 2005 is perhaps one of the most powerful and most over looked control. This control is new to Visual Studio 2005, comes in both Win Forms and ASP.NET versions, and is freely redistributable. Essentially, the report viewer control allows developers to embed and distribute reports with applications.
[ReportViewerRedistributable]
Additional Resources: http://www.gotreportviewer.com/