nmzmail is a tool to use the namazu2 search engine from within a mail
reader such as mutt to search mail stored in maildir folders. Based on
the result of the namazu query, nmzmail generates a maildir folder
containing symbolic links to the mails matching the query. Mutt and
other mail readers can make it easy to use nmzmail with a simple
macro.

Features:
* fast mail searching even with large number of mails
* incremental index building
* rich query language including regular expressions (see the namazu
  documentation)
* integrates nicely into mutt
* query history

WWW: http://www.ecademix.com/JohannesHofmann/nmzmail.html