The best open source alternative to Carbon Copy Cloner is Clonezilla, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 25 alternatives to Carbon Copy Cloner and five of them is open source so hopefully you can find a suitable replacement. Other interesting open source alternatives to Carbon Copy Cloner are FOG Project (Free, Open Source), FSArchiver (Free, Open Source), WereSync (Free, Open Source) and dd for windows (Free, Open Source).
FOG is a free open-source cloning/imaging solution/rescue suite. A alternative solution used to image Windows XP, Vista PCs using PXE, PartImage, and a Web GUI to tie it together. Includes featues like memory and disk test, disk wipe, av scan & task scheduling.
FSArchiver is a system tool that allows you to save the contents of a file system to a compressed archive file. The file system can be restored on a partition which has a different size and it can be restored on a different file system.