I use rsync to backup my folders and after the initial run, all other runs just update things so it's very quick. For that reason, I don't even bother using cron for that.
You need to put a partition on the second drive and format it as ext3 for example:
mount /dev/hdb1 /mnt/images -t ext3
Put an entry in the /etc/fstab so it's available every time you boot.
/dev/hdb1 /mnt/images vfat defaults 0 0
To make it writable for users with a group id of 500, edit the /etc/fstab file to include the following line /dev/hdb1 /mnt/win vfat gid=500,umask=002 0 0
Run the rysnc job, I usually run it a couple of times to make sure everything went ok.
rsync -av --delete-after /home/fred /mnt/images