if you can mount a linux fs, you're able to mount a vfat too. As root, type
# mkdir /mnt/data (or whatever name you choose)
# mount -t vfat /dev/hdc1 /mnt/data
change hdc1 to the actual partition (hdc1 is on secondary master, hdb1 on primary slave, etc.)
to have it mounted at boot time add a line similar to this to your /etc/fstab:
/dev/hdb1 /mnt/data1 vfat rw,umask=0 0 0
if you want it readonly, use ro instead of rw
See also this:
http://www.linuxquestions.org/questi...5&pagenumber=1
Note that vfat is slower than most (all?) native linux filesystems, so it's not a ggod choice for a file server. It has no permissions too. If you have <40gb data, you should imo only use 40gb for your fat partition, fill it on your win box, then on linux create a 40gb ext2 or reisefs partition, copy files to it, and keep the vfat for backups.