If you would like to edit XML files in Visual Studio and use intellisense, this is what you have to do:

Locate your schema, then copy it to C:\Progam Files\Microsoft Visual Studio .NET 2003\Common7\Packages\schemas\xml.

Then open your XML document and reference the schema by its namespace URI in the root element.

If you want to automate the update of your schema files the use scripting on the Visual Studio's OnStartupComplete event.