Assuming you only have one USB Flash drive, it should be named sda1 and be in /dev. If sda1 is not the name for your drive, use some fashion of hardware browser to find the name.
To do this the quick way type this in the terminal: mount -t auto /dev/sda1 /mnt
This automatically determines the file system and mounts the device sda1 in the folder /mnt. Just point Nautilus or Konquorer to that folder and the contens of the USB drive will be there.
You're going to need to edit the /etc/fstab file to make future mountings quick and easy. Use a edit program of your choosing. Add this line into fstab and click save. If you can't save the file due to lack of permissions, use this command in the terminal: chmod u=rwx /etc/fstab
/dev/sda1 /mnt/flashdrive auto defaults,users,noauto 00
/dev/sda1 is telliing the computer what device to mount.
/mnt/flashdrive is telling the computer where to mount it. In this case, you would have to use the mkdir command and create the flashdrive folder.
auto tells the computer to automatically figure out the file system.
defaults,users,noauto tells the computer to manage the USB drive in the usual fashion, make it avaliable to all users of the computer, and not automatically mount the drive on startup, as it may not be plugged in.
0 0 hell, I don't know what that means! It's complicated, I hear.
Now, in the terminal, use: mount -a
This command automatically mounts everything in the fstab file that isn't already mounted. If you want to unmount something use the command: umount /dev/sda1
If it says the device is busy, use: umount -l /dev/sda1
This makes the device unmount as soon as it is not busy.
Unmounting a USB storage device is a NECESSITY, or no changes to the device will be saved. Like new files you added, for example.
You can put an icon to the flash drive on your desktop. Just right click go to new, device, USB storage. You should probably be able to figure that one out. Enjoy. Feel free to ask questions if I'm not 100% clear or something dosen't work.