simple question? -- forwarding email

I assume this is a simple newbie question:

        How do I call sendmail to forward a message from procmail?  

Details: 
I invoke procmail with this in my .forward file:

        "|IFS=' ' && exec /usr/local/bin/procmail -f- || exit 75 #david"

I'd like to use it to forward mail for other users.  This works ok:

        :0:
        * ^TO_.*wtp*
        /usr/spool/mail/wtp

However, what I really want to do is to forward the mail elsewhere.  That is,
I really want to invoke a shell script to say "send message to 
wtp(_at_)foobar(_dot_)com"
Any ideas on how I could do this?

David Jaffe
david(_at_)jaffe(_dot_)com