I'm not sure if this will work in Fedora (works in Slackware) but here goes. As root
mount -t vfat /dev/sda1 /mnt/usbkey
The /dev/sda1 might be /dev/sda2 and so on. /mnt/usbkey can be anything: /mnt/cdrom, /mnt/floppy.
If you want any user to be able to mount it add this line to your fstab
/dev/sda1 /mnt/usbkey vfat noauto,users 0 0
Again, make any necessary changes to /dev/sda1 and /mnt/usbkey (Remember, the directory you mount to has to exist: 'mkdir /mnt/usbkey').