> /etc/init.d/sendmail stop
> chkconfig --level 2345 sendmail off
> find /var/spool/mqueue -type f -exec rm -f {} \;
>
> That'll empty out your queue and you won't have to worry about
> it building up again, pesky thing!
>
Hmm...it will still build. To really fix it, you need to do one more step:
rpm -e --nodeps sendmail
Now that is a permanent solution.