you can simply do (as root) an
That will list all the drives and their partitions.
If the drive had no partitions before hand, it will be easy to identify...
If you still can't find the drive, look into '/etc/fstab' and exclude the drisks you find from the 'fdisk -l' result. That should leave you with a single disk. If that disk has partitions, mount then read only and make sure you're not abut to wipe the wrong disk.
As of now, the drive will be sdz
Create a partition (or more) and save. You might have to reboot for the kernel to take the changes.
Now, just use the following command to format it in ext3.
# mke2fs -j /dev/sdz
now add the disk to the fstab and mount it.
I hope this helps. I'd give you more details but i don't have a shell at hand.