First of all, fat32 cant handle permissions.
Since only root user can mount partitions, they will be owned by root. It can be solved by adding entries to fstab.
Or, from commandline (which I assume is what you tried)

mount -t vfat -o user /dev/something /some/mountpoint

notice the -o parameter. If you want it avail for every user, that parameter should be -"o users" instead