Semantic MediaWiki extension for MediaWiki  have been released in version 0.6 recently. Core changes include:
- New Special:Ask for directly browsing query results and for testing queries.
- New output format "timeline" for inline queries that deal with dates, based on Simile Timeline.
- Complete RDF export is now possible with a maintenance script. Various further improvements in RDF export.
- New "service links" feature: any attribute can provide configurable links to online services.
SMW 0.6 now will run only the current MediaWiki 1.8 and PHP5. The new version also comes with an updated online documenation  that describes the functionality in detail. Development and usage is discussed on our mailinglists .