Tools for creating W3C XML Schema files
From XSLT's creator
James Clark, technical lead on XML 1.0, editor of XSLT, and co-author of RELAX NG, comes yet another piece of software people didn't think possible.
has a simple command-line interface for converting from DTDs to RELAX NG or RELAX NG Compact Syntax - or W3C XML Schema. It can also generate any of these from sample XML documents.
From RELAX NG Compact Syntax to W3C XML Schema:
java -jar trang.jar myschema.rnc myschema.xsd