Open the file .procmailrc (located in your home directory) with a text editor. You should see text similar to the following:

:0fw
| /usr/local/bin/spamc -f -s 256000

:0e
{
EXITCODE=$?
}

:0:
* ^X-Spam-Status: Yes
mail/caughtspam

At the end of the file, after mail/caughtspam, add the following lines:

:0
! address_to_forward_email_to

The above setup will put spam emails into the mail folder caughtspam, and all other emails will be forwarded to the address you specify after the !

If you only want to forward a copy of the email, add a "c" after the ":0" like this:

:0c
! address_to_forward_email_to

This will then forward any "non-spam" emails to the specified address, and will also keep a local copy in your inbox.