Been well into the semantic web lately and today I stumbled across a search engine that crawls and index data for the semantic web: Swoogle, it's not only a "quick and dirty" rdf data lookup, but it also does Terms, Classes and Properties based search, cache of all documents, N-Triples of any document, a visual representation of the documents indexed, and: a web service interface.
So far 700.000+ files is in the database, with more comming, the search is implemented with PHP, and the site itself is implemented in PHP Nuke. A really interesting and good concept search for the semantic web. Bookmark this one.