Sendmail+Spamassassin+Procmail and /etc/procmailrc

Hi,

I need to have spamassassin tag spam mail for all users, and have procmail
divert the spam to a local mailbox such as spam@mydomain.com (a local user
called spam) .

I created /etc/procmailrc and entered the following:
========================
:0 fw
* < 256000
| /usr/bin/spamc -f

:0 w
* ^X-Spam-Status: Yes
|procmail -d spam
========================
But that seems to have some recursive effect on spamassassin , it took too
much CPU time and will delivert the spam to mail box only after I changed
/etc/procmailrc to :

========================
:0 fw
* < 256000
| /usr/bin/spamc -f
========================

There is a lot of info on how to make procmail divert spam to a directory,
but I could not find any that talks about diverting spam to a local mailbox.

Sabah