This is a script for converting an attached audio file to an MP3
upon receipt of an email.  It can be invoked by adding something like
this to your ~/.forward file:

"|exec /usr/bin/ruby /home/vmail/vmail.rb || exit 75"

It'll extract the attachment, encode it with 'lame', then build a new email
message back to the address where the message originated with the MP3
attached.  The script is also dependent upon 'sox', to uncompress
the source WAV file.

This looks for the phone number in the subject of the email, this script is
customized for the voicemail e-mail attachments from our NetSapiens PBX.