Mailing to all users

Hi.

How can I use procmail to send a message to all users ?

I have a file with the list of users and another with the message.
I'm asking for something like:

#
for name in $( awk '{print $1}' $1 )
do
  procmail $name $2
done
#

where:

$1 = list of users
$2 = message


Thanks.

Hernan Sanchez