The Perl port of the Java Lucene freetext search engine.
As far as we know, this is no longer under active development.
- KinoSearch - same goals, same history, still perl, better implementation.
- MySQL - has native freetext search. Easy, generally just works. The freetext bits do not offer much in the way of configuration but you do get all the power of a sql query. I've seen it handle 100,000 web page sized documents without blinking but your mileage may vary.
There used to be a wiki here. It was inactive for over a year, so it left the building.