There are a few fairly good clone utilities available; although I use a
donationware (runs uninhibited direct from download online) by Mike
Bombich named Carbon Copy Cloner, with a good amount of inform-
ation available at the home and download pages for reference; users
have had good use of Super Duper, CloneX, to do backups & clones.
Other utilities, such as the Disk Utility in your system install/boot disc
can be used to move a bootable archive of your system between disks.
Drive Genius (a retail software product) is said to be able to utilize
clones, but I have no experience in that product; although I do own it.
I like Carbon Copy Cloner, and test my clone's ability to run the Mac
before attempting to zero-reformat the machine's internal hard drive, etc.
A simple search of Mac sites (I use google.com/mac) can bring up
discussions specific to these third-party tools. The home page of
Mike Bombich's Carbon Copy Cloner is worth a detailed look into.
OS specific versions are available.
http://www.bombich.com/software/ccc.html