No problem Clarke,
A clone is just what it says. It is an exact copy of the parent.
Unlike the mac os's prior to X, you cannot just drag and drop your system or many of it's folders to another hard drive/partition to copy them. There are invisible files and links between files that have to be maintained. No problem, you just use a program for cloning. I have used Carbon Copy Clone for years and for making a simple clone it is easy and works well.
To start with, you need another hard drive. You will need an external firewire drive to make it bootable (a combo firewire/usb is fine but just usb won't work on our macs. The newer Intel macs are usb bootable but ours just work on firewire). Once you have the external drive plug it in, turn it on and format it using Disk Utility to hfs+ journaled. If you want to split the drive in 2 or more parts you can do it now. Keep in mind that you need at least as much space on the clone as the parent takes. To split the drive later would require erasing it's contents so decide if you want to have more than one copy of your system (one for testing the other for backup or what ever). This is all done with Disk Utility.
Now that you have the destination for cloning download CCC
http://www.versiontracker.com/dyn/moreinfo/macosx/13260
(This site is also a great one for downloading share ware, updates, etc. so book mark VersionTracker.com).
First open your preferences and select Energy Saver. Set it to a couple of hours or just turn it off. You don't want to sleep during the clone process. You might also want to plug your laptop into the power supply.
Once downloaded, drag CCC to the Applications folder, start it and you will get the panel for cloning. Click the preferences and select "repair permissions before cloning and make bootable".
Close the preferences and on the main panel your source is your current hard drive. The destination is the external drive (or one of it's partitions if you decide to split the hd). Click the lock at the bottom to bring up the authentication window, enter your name, click the clone button and go watch tv or something.
When it is finished you will get a window telling you so. Don't do web surfing or Photoshop work while cloning. If you can't remember what programs are running before cloning then just restart your mac and go directly to CCC or whatever program you decide to use (some like SuperDuper also available on VersionTracker.com. Just enter "clone" in the search window).
When it is all done try booting from your clone. You hold the option key down at boot and with the firewire drive on you should get a screen with both the laptop's hard drive and your external drive as valid start drives. Select the external and it should boot. If it does not go back to your main drive, open preferences and select Startup Disk. Your clone should appear there. Select it and restart. If it still does not work then your clone is bad but in 3 years of cloning I think that this happened one time.
If you ever mess up the main laptop drive or it dies you can start your laptop off the clone, start CCC, erase the laptops messed up/or new drive and clone your backup to the laptop. Now a catastrophic failure of the system or the hard drive won't cost you any lost info and time.
I keep several clones on several drives for backup. Every few months I use dvd's to back up critical customer files but in the interim it is clones of the main drive. When major updates to the system come along and I'm going to install them it is never without making sure that I have an up to date clone to fall back on. Years ago I had a drive fail that I thought was backed up on cd's. It was an expensive lesson in backing up. Since then I have had half a dozen hard drives fail so my paranoia with multiple clones. Cloning is the easiest way to make sure everything is backed up.