Here is a quick and easy way to save and restore hard disk images using dd, netcat and gzip.

To Save An Image:
On the server: nc -l -p 7000 | dd of=Output.img
On the client: dd if=/dev/sdb | gzip -9 | nc 12.34.56.78 7000

To Restore:
On the client: nc -l -p 7000 | gzip -dc | dd of=/dev/sda
On the server: dd if=Output.img | nc 12.34.56.78 7000

I just boot the client using an Ubuntu live-cd, all the neccessary tools are already installed. I store my images gzipped to save space, I just copied a 40 GB disk and the image file compressed down to 4.4 GB!