This is a simple script that converts emails containing uuencoded files to MIME. The script is written in Ruby and makes use of Matt Armstrong's excellent RubyMail mail handling library. I use it from a rule in my procmailrc:
# Convert from uuencoded to MIME :0 fw |/usr/bin/ruby $HOME/bin/uu2mime.rb
add Header
fix nmsg/msg typo
fixup pgp headers for inlined signatures and encryption according to http://www.tldp.org/HOWTO/Mutt-GnuPG-PGP-HOWTO-8.html#ss8.2