Those who care may already know that on Feb 25 W3C released a working draft for public comment of XML-Schema, with a last call for review expected in March.

Perhaps of more general interest is XML Schema Part 0: Primer at http://www.w3.org/TR/xmlschema-0/

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From the abstract:

"XML Schema Part 0: Primer is a non-normative document intended to provide an easily readable description of the XML Schema facilities and is oriented towards quickly understanding how to create schemas using the XML Schema language."