Comment Solr is Lucene-based and understands Word files (Score 1) 232
The upcoming Solr 1.4 release (http://lucene.apache.org/solr) includes the Tika document parser. You can throw Word, PDF etc files to it, and it will index them for you. Solr is a web service; a few hundred lines of PHP would be enough to use the Solr to index your shared volume, and a again that much for a web-based search tool.