mbox2mdir is a small program to convert mail stored in UNIX mbox format to
qmail's Maildir format. It can (optionally) also truncate the source mbox file
upon successful conversion. I use it to move mail delivered by /bin/mail or
sendmail to qmail Maildir folders, but of course there are many other possible
uses for it.

WWW: http://sageshome.net/oss/mbox2mdir.php