As root, pico /etc/fstab
Add this line:
/dev/hda8 /windata vfat user,umask=000,rw 0 0
Make sure that /dev/hda8 is in fact pointing at your Windows data partition.
Note also that this assumes that the Windows data partition is formatted as FAT32, hence the “vfat”.
Before you can actually mount your Windows partition, you need to mkdir /windata as root.
Note that originally I had this line in /etc/rc.d/init.d/rc.local:
mount -t vfat -w -o user,umask=000 /dev/hda7 /mnt/windata