KinoSearch is good (I use it) but it will require some code writing to get the document aggregation and parsing working, especially if you have non-text (e.g. Word and PDF) docs.
Swish-e (http://swish-e.org/) is what powers search.cpan.org (last I knew). It has a binary tool for indexing, and a Perl API (SWISH::API) for searching. There are also out-of-the-box .cgi scripts for searching.
Disclaimer: I am a developer for both KinoSearch and Swish-e. :)