Parallels user Mark (aka) Clalron has whipped up a nifty little utility called VM2Go and he just released it as beta in the Parallels forums. The app provides a list of all the virtual machines on your Mac, shows their actual disk space usage, allows VMs to be transferred to iPods or external drives, allows you to backup your VM to CD or DVD and restore it from CD or DVD as well.
Although I haven't had a chance to try it yet since I won't be on a Mac that has Parallels on it until later today, but it sounds like it will be quite useful! If any of you get a chance to try it out, please let us know your thoughts - and be sure to also send feedback and bug reports to the developer also so he can improve upon future releases.
The user guide and mac.com download link location are temporary, as is the icon - which is a good thing because the icon currently looks like the Transmit icon with a bad case of food poisoning.
More info and the download link can be found in the Parallels support forums.