Linux 2.4 and above -
First plug the device into the USB port of your computer
Execute: cd /etc/sysconfig/ ( cat /etc/sysconfig/hwconf | more )
Check the device information in hwconf and write down the mount point.
Make a directory in /mnt (ex: mkdir /mnt/usbHD )
Then execute: mount /dev/sda1 /mnt/usbHD (if mount point was .dev/sda)