Materials: New 3.5″ SATA Hard Disk
Carbon Copy Cloner: http://www.bombich.com/software/ccc.html
Usb/Sata Cable or External Case
OSX Boot CD
USB Thumb drive

Method: Connect new hard drive to USB Sata Cable and connect to iMac.
Download Carbon Copy Cloner, mount the image and copy the application to the Thumb drive.
Boot the mac from the OSX CD, select your language and then quit the installer, but dont reboot.
From the utilities menu select disk utility and partition the New disk.
Quit Disk Utility.
From the utility Menu, start Terminal.
type cd /Volumes/[Return]
cd “The name of your USB Drive”[Return] if you are not sure, type cd and press tab and it will give you a list. if you type the first couple of letters and press [Tab] it should fill in the rest for you, very handy if you have spaces in the name

cd Carbon\ Copy\ Cloner.app/[Return]

cd Contents/[Return]

cd MacOS/[Return]

./Carbon\ Copy\ Cloner[Return]

This will start the application. At this point you have the perfect scenario of being boot from an operating system and running the program you want without touching either either Hard Disk, so the copy can happen without any files being open.
Select the Source Dive and the Destination Drive.
Double check you got the source and destination correct, or you will blank your data!! You have been warned! If you partitioned the new drive, your destination should be called “Untitled 1″.

Select “Copy Everything”
Dont worry about the message that the destination drive wont be startable because you cant boot from a USB drive. We will be putting the drive internal as soon as we are finished…

[Clone]

Wait for an hour or two..

When it is all done, quit everything and restart, but when the machine chimes that it is rebooting, push the power button in for 10 seconds till the machine turns off.
Pull the machine apart and put the new hard disk in.
Startup the machine and hold the mouse button in to eject the CD.
The system should boot exactly as it did before but this time from it’s new Hard Disk.