Please have a look here:
These are no traditional system image (files) like the ones you got for example with norton ghost, but they have some pro's:
1) Fast compressed transfer over the internet.
2) Easy, even automated backups
3) Easy restore even on dedicated servers where you only have a mini linux rescue system.
4) You can restore the backup on a different disk with a different disk geometry or even a server with different hardware without problems, as long as your linux kernel supports the hardware of the new server. I've copied a fully installed linux server with this method from a via mini-ITX borad with via processor to a 1HE system with Intel P4 system flawlessly.