create crontab

[Mad Unix]

I have mail-hots serving 300 users pop3/imap through qmail
I manually remove old entries manually which older than 30 days
for each user
find /home/vpopmail/domains/sdcdom/user001/ -type f -mtime +30 -exec rm {} 
";"
find /home/vpopmail/domains/sdcdom/user002/ -type f -mtime +30 -exec rm {} 
";"
...etc.
 How can i add this entry into my crontab, to run at the end of the Week at 
6 clock
in the morning.
 am using Linux RHEL 3
 Thanks