I'm happy to announce now version 0.4 of this software which, thanks to improvements in Lucene.Net and patches from the Beagle hackers, is a lot more stable. Previous versions had some nasty locking issues that could kill the server quite dead.
XmlIndexer is a simple indexer. Given a rulefile that maps XPaths to Lucene keys, it can be taught to index any XML file you should care to give it. I use it to provide search functionality to legacy applications, which then need only to expose their data as XML and call a few simple web services to perform a search.
Of related interest is the new Apache Incubator Solr project, which provides a fancy search server based on Lucene, doing the same as my indexer, and much more.
XmlIndexer requires Lucene.Net version 1.9.1. For extra points, apply the locking patches from Beagle to Lucene.Net before building. As a courtesy I include a Lucene.Net DLL I made this way in the download.