Namazu

Namazu is a full-text search system intended for easy use. Not only does it work as a small or medium scale Web search engine, but also as a personal search system for email or other files. Supported document types: HTML, Mail/News, MHonArc, RFC, TeX (with detex), man (with groff), Word (with wvWare), PDF (with pdftotext) and plain text.

http://www.namazu.org/