intelligent search on docbook-xml-douments

["Sebastian Fey" <fey@parsytec.de>]

hi,

Our documentaion is not only available as print version but also online (html).
Id like to make use of the fact that it is structured as XML,
when adding a search-engine to the documentations home-page.
Not yet but maybe later we could also add topic-maps or some RDF-structure, 
but at the moment im looking for some search-engine, 
that just benefits from the fact, that the html-files result from XML.

any pointers?

thx in advance,

Sebastian