To access a usb flash drive you can modify your /etc/fstab file like this:

/dev/sda1		/mnt/usb_flash		vfat noauto,users,rw,umask=0 0 0

Then as root do this: [ mount -a ]
This is what my /etc/fstab looks like on my system which is 2.4.20-6 ( Red Hat 9 )

LABEL=/                 /                       ext3    defaults        1 1
LABEL=/boot             /boot                   ext3    defaults        1 2
none                    /dev/pts                devpts  gid=5,mode=620  0 0
LABEL=/home             /home                   ext3    defaults        1 2
LABEL=/opt              /opt                    ext3    defaults        1 2
none                    /proc                   proc    defaults        0 0
none                    /dev/shm                tmpfs   defaults        0 0
LABEL=/tmp              /tmp                    ext3    defaults        1 2
LABEL=/usr              /usr                    ext3    defaults        1 2
LABEL=/usr/local        /usr/local              ext3    defaults        1 2
LABEL=/var              /var                    ext3    defaults        1 2
/dev/hda8               swap                    swap    defaults        0 0
/dev/cdrom              /mnt/cdrom              udf,iso9660 noauto,owner,kudzu,ro 0 0
/dev/fd0                /mnt/floppy             auto    noauto,owner,kudzu 0 0
/dev/sda		/mnt/cam		vfat noauto,user 0 0
/dev/sda1		/mnt/usb_flash		vfat noauto,users,rw,umask=0 0 0 

You can see where I have added the last line.
This lets you access the "drive" just like a floppy or a cdrom.
More about the mount command here
This command mounts the flash drive:
[ mount /mnt/usb_flash ]
I used a 512mb disk "SanDisk CruzerMicro" on a "Dell Optiplex GX110" machine running GNU/Linux kernel version 2.4.20-6 ( Red Hat 9 )