From: http://scraping.apievangelist.com/tools.html

Also: http://tika.apache.org/

The Apache Tika™ toolkit detects and extracts metadata and text from over a thousand different file 
types (such as PPT, XLS, and PDF). All of these file types can be parsed through a single interface, 
making Tika useful for search engine indexing, content analysis, translation, and much more. You can 
find the latest release on the download page. Please see the Getting Started page for more information 
on how to start using Tika.