Author of http://www.searchmorph.com/
Some contributions to Lucene gathered together here: http://www.tropo.com/techno/java/lucene/
Also "more like this" query expansion: http://nagoya.apache.org/eyebrowse/SearchList?listId=&listName=lucene-user%40jakarta.apache.org&searchText=MoreLikeThis&defaultField=subject&Search=Search