If you have a PC that's on 24/7 you can run updates automatically. Open your favorite cron editor as root (I prefer kcron or webmin) and open a new job. In the command field put: /usr/sbin/urpmi.update update and have it run every day at a specified time and save it. Open another new job and put in: /usr/sbin/urpmi --media update --auto --auto-select and run it every day at a time after the first job. Save that job too.
That's it

PS. Fill it the complete path, ie. /usr/sbin/, else it won't work.