Clonezilla - the opensource clone system

"You're probably familiar with the popular proprietary commercial package Norton Ghost®, and its OpenSource counterpart, Partition Image. The problem with these software packages is that it takes a lot of time to massively clone systems to many computers. You've probably also heard of Symantec's solution to this problem, Symantec Ghost Corporate Edition® with multicasting. Well, now there is an OpenSource clone system (OCS) solution called Clonezilla with unicasting and multicasting! With DRBL and network boot enabled client computers, the only thing you have to prepare is a Clonezilla server. You do not even have to prepare a bootable CD or floppy with Partition Image for every client computer."

http://clonezilla.sourceforge.net/