Step 1: open your log file for viewing to determine the correct device name for the USB Drive
open a shell and su to root.

tail -f /var/log/messages

now plug in the usb drive and watch the scrolling messages

Feb 8 10:43:43 localhost kernel: usb 2-2: new full speed USB device using address 6
Feb 8 10:43:43 localhost kernel: scsi2 : SCSI emulation for USB Mass Storage devices
Feb 8 10:43:44 localhost kernel: Vendor: ICSI Model: CF Card Rev: 2.7C
Feb 8 10:43:44 localhost kernel: Type: Direct-Access ANSI SCSI revision: 02
Feb 8 10:43:44 localhost kernel: SCSI device sdb: 125184 512-byte hdwr sectors (64 MB)
Feb 8 10:43:44 localhost kernel: sdb: assuming Write Enabled
Feb 8 10:43:44 localhost kernel: /dev/scsi/host2/bus0/target0/lun1: p1
Feb 8 10:43:44 localhost scsi.agent[22707]: sd_mod: loaded sucessfully (for disk)
Feb 8 10:43:45 localhost scsi.agent[22753]: sd_mod: loaded sucessfully (for disk)
Feb 8 10:43:45 localhost usb.agent[22766]: usb-storage: already loaded
ctrl+c to break out of the log view

it identified my USB device as sdb so I now need to mount it. sdb is the device name so when I mount it I will mount sdb1 to mount the first partition on the device.

I'll start by creating a folder to mount the drive to

mkdir /mount/usbdrive
then I'll issue the command to mount the drive
mount /dev/sdb1 /mount/usbdrive


should be that easy..

and if you want any regular user to be able to mount and unmount the drive you will need to edit your fstab file to add an entry for the USB drive.