These two tools are rather simple, but can be extremely useful. The first is the ASP.NET Version Switcher, which can be used to switch the version of ASP.NET that a virtual directory is running under. The second tool is the Visual Studio Converter, which can be used to switch a project file from Visual Studio .NET 2002 to Visual Studio .NET 2003.
http://www.denisbauer.com/NETTools/ASPNETVersionSwitcher.aspx.
