Henry S. Thompson and Richard Tobin have released XSV 2.8-1, a partial W3C XML Schema Validator for Linux and Windows. There's also a web form based interface. This release fixes bugs and can now validate XML 1.1 documents and read XML 1.1 schemas (though the W3C XML Schema language still doesn't support XML 1.1 names, so documents that actually use XML 1.1 features are likely to be invalid).
Michael Kay has released Saxon 8.1.1, an implementation of XSLT 2.0, XPath 2.0, and XQuery in Java. Saxon 8.1 is published in two versions for both of which Java 1.4 is required. Saxon 8.1B is an open source product published under the Mozilla Public License 1.0 that "implements the 'basic' conformance level for XSLT 2.0 and XQuery." Saxon 8.1SA is a £250.00 payware version that "allows stylesheets and queries to import an XML Schema, to validate input and output trees against a schema, and to select elements and attributes based on their schema-defined type. Saxon-SA also incorporates a free-standard XML Schema validator. In addition Saxon-SA incorporates some advanced extensions not available in the Saxon-B product. These include a try/catch capability for catching dynamic errors, improved error diagnostics, support for higher-order functions, and additional facilities in XQuery including support for grouping, advanced regular expression analysis, and formatting of dates and numbers." Version 8.1.1 is a bug fix release. Upgrades from 8.x are free.