Will there be a lot of documents? Will the search need to be fast? If so, you might consider KinoSearch or Lucene.

Both systems build efficient searchable text-based indexes of the content you wish to search, and allow you to later perform searches on that index.

In both systems you'll still need to have a way to export the documents as ascii text, so unless you can pre-arrange that ahead of time, perhaps you might use Win32::OLE to drive a "batch" export of the ascii versions.

-David