ArcGIS 9.3 was released today. The following link is a video demo of the new features/enhancements in ArcGIS 9.3 (ArcGIS Desktop 9.3 Demos).
ArcGIS 9.3 supports Visual Studio 2008 in ArcGIS Desktop, ArcGIS Engine, and ArcGIS Server for customization and development. In addition, ArcGIS 9.3 continues to support Visual Studio 2005. ArcGIS 9.3 still has the Visual Basic (VB) 6 Software Developer Kit (SDK) for ArcGIS Engine and ArcGIS Desktop. ArcGIS Server 9.3 supports .NET 3.5.