While hard drive cloning is typically performed by computer techs or admins looking to roll out many identical systems in a short time, there are circumstances when you may need to do this on your home system. When this time comes, an open source tool you may be interested in is FOG.

Fog is a Linux-based, free and open source computer imaging solution for Windows XP and Vista that ties together a few open-source tools with a php-based web interface. Fog doesn’t use any boot disks, or CDs[...]. Also with fog many drivers are built into the kernel, so you don’t really need to worry about drivers (unless there isn’t a linux kernel module for it). Fog also supports putting an image that came from a computer with a 80GB partition onto a machine with a 40GB hard drive as long as the data is less than 40GB.

From the description, this tool should meet just about any needs you have, and from the sounds of it, professionals could make use of it as well. Overall, if the need comes up, FOG appears to be a great alternative to commercial products.