To get the most out of your VMs and backup and restore them in the most reliable way you must install VMware tools in your guests.
As well as providing better mouse & video drivers it provides an API to the host providing IP, clock information and installs VM startup, VM shutdown, VM freeze & VM thaw scripts /usr/sbin/pre-freeze-script and /usr/bin/post-thaw-script.
http://www.vmware.com/pdf/vi3
