I’m posting this more as a reminder for myself. Where exactly are you supposed to place XSD files to give you intellisense for XML files in Visual Studio.NET?
Visual Studio.NET 2003
C:\Program Files\Microsoft Visual Studio .NET 2003\Common7\Packages\schemas\xml
Visual Studio.NET 2005
C:\Program Files\Microsoft Visual Studio 8\Common7\Packages\schemas\xml
This is useful for such things as Nant.xsd and UrlRewriting.xsd.
To get intellisense for NAnt, you have a couple of other steps to do.