I have used this great software since it has been available and  is donationware called Carbon Copy Cloner to backup, clone and synchronize a Mac Hard drive.  It is the functional equivalent of Ghost on PC.  It has always worked for me and never had a problem with the images it created.  If you want to make mass deployments of macs a breeze and can’t afford Mac OS X Server 10.6 for $500, it will do the job very well.