Ghosting is essentially the copying of a drive or partition to another drive or partition. Formatting and partitioning information are usually transferred from the source drive to the destination drive - the destination becomes a "clone" of the source. It's usually done booting up the ghoster and the ghostee from floppies created from within the ghost software.
I use the Norton Ghost software. I've copied drives via a parallel cable between laptops or two desktop drives connected as a master and a slave to the same IDE cable.
The coolest of them all is the ability to boot a laptop connected to the network and have it receive it's hard drive image from a server on the network. It takes about 8 minutes to have a freshly rebuilt and pre-configured laptop based on an image that I painstakingly created and saved to the Ghost server.
I've heard that there's other makers of ghosting software, but I've had no experience with them. I think Norton has the market pretty much cornered.
Sweating like a rancid chunk of pork