Hi, I uploaded a better version than I posted here on sourceforge: http://sourceforge.net/projects/mutt-mb/
The version posted here doesn't free all the memory it allocates --- doesn't matter, but it's ugly. That's fixed in the version on sourceforge, plus a few extensions. The program can be used directly within ~/.muttrc, see the documentation on sourceforge (doc is included in the mutt-mb.tar.gz).