Whenever I migrated a linux server using the VMware Converter, my ethernet devices disappeared. I found a quick and easy way to restore them without any fancy work. Just delete (or move) the file /etc/udev/rules.d/70-persistent-net.rules. This file is used to associate the eth devices with a mac address so that they always come up the same way. When VMware converts a machine, it assigns a different mac address to the virtual ethernet adapter, so this file needs to be deleted.
Thanks to http://techblog.romero.id.au/2009/06/ubuntu-missing-eth0-after-cloning-in-vmware/ for the explanation.
