Applications can be developed on Visual Studio 6 using the SDK 2.5
Microsoft® Visual Studio® 6.0 is a powerful developer tools suite for Windows and Web applications. In this section of the Library you'll find information on Visual Studio 6.0 itself and the core components found in version 6.0: Visual Basic®, Visual C++®, Visual J++®, Visual InterDev®, and Visual SourceSafe®. To learn more about the latest version of Visual Studio, visit the Visual Studio Developer Center.

Applications can be developed on Visual Studio 2005 using the SDK 2.6
Microsoft Visual Studio 2005 is a complete set of development tools for building ASP.NET Web applications, XML Web services, desktop applications, and mobile applications. Visual Basic, Visual C++, Visual C#, and Visual J# all use the same integrated development environment (IDE), which allows them to share tools and facilitates in the creation of mixed-language solutions. Check out the Visual Studio 2005 Developer Center