Here's something I've noticed you can do with SQL Server 2005 and Visual Studio 2005.
Take a set of XML documents with the same basic structure. Load one into Visual Studio 2005. Click on the XML menu, Create XML Schema. Make any refinements to the XML schema that is produced that you want, based on your knowledge of the document content. Note that the XML schema is created without the "targetNamespace" attribute. Save to disk.
Open an SSMS 2005 (that's SQL Server Management Studio) query window. Paste in your XML schema and use it to create an XML SCHEMA COLLECTION (of one XML schema). Now you can use the XML SCHEMA COLLECTION to strongly type an XML data type, in a SQL table column, variable, what-have-you.
You can also do XQuery (strongly typed) without using namespace declarations in XQuery preface or namespace prefixes in your query text.
This works because each XML SCHEMA COLLECTION is permitted to have a single "no namespace" schema. SQL Server wouldn't recognize the noNamespaceSchemaLocation (yes, schemas with no namespace are allowed by the XML Schema spec) even if you had it because it does not resolve schemas that don't "live in" SQL Server. And the VS-produced schema specifies attributeFormDefault="unqualified" and elementFormDefault="qualified" so the queries work.
That's for the truly lazy and after all, probably evil to true schema afficianados…so go back and put a namespace in your XML Schema, and use prefixes or default element namespace in XQuery preface.