Cannot identify CF drive

Since the drive shows up on your desktop that means Ubuntu recognizes and mounts it. So all you need to do is determine the device that was mounted. I have attached a compact flash to my laptop and when I type mount I see this:

$mount
/dev/sda5 on / type ext3 (rw,relatime,errors=remount-ro)
proc on /proc type proc (rw)
... <snip /> ...
/dev/sda1 on /mnt/dell type vfat (rw,utf8,umask=007,gid=46)
/dev/sda2 on /mnt/windows type fuseblk (rw,nosuid,nodev,allow_other,default_permissions,blksize=4096)
/dev/sda6 on /home type ext3 (rw,relatime)
binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,noexec,nosuid,nodev)
gvfs-fuse-daemon on /home/tima/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=tima)
/dev/sdc1 on /media/5bee9422-2fe5-45f5-8d6b-dccc67f151ea type ext3 (rw,nosuid,nodev,uhelper=devkit)
$

Most likely the last thing mounted will be your compact flash as it is with mine. Also you can check the size of the device.

$
$df -lh
Filesystem Size Used Avail Use% Mounted on
/dev/sda5 23G 5.8G 16G 28% /
udev 1.8G 324K 1.8G 1% /dev
none 1.8G 628K 1.8G 1% /dev/shm
none 1.8G 100K 1.8G 1% /var/run
none 1.8G 0 1.8G 0% /var/lock
none 1.8G 0 1.8G 0% /lib/init/rw
/dev/sda1 102M 8.4M 94M 9% /mnt/dell
/dev/sda2 18G 17G 1.3G 93% /mnt/windows
/dev/sda6 103G 83G 16G 85% /home
/dev/sdc1 958M 23M 887M 3% /media/5bee9422-2fe5-45f5-8d6b-dccc67f151ea
$

My 1G compact flash shows up as 958M so /dev/sdc1 is my compact flash. Yours should be similar and you can use that device (without the trailing '1') with fdisk. For example I would use "sudo fdisk /dev/sdc". You may want to use a graphical disk/partition manager such as gparted or ubuntu 9.10 (karmic) includes a very nice "Disk Utility".