Download Carbon Copy Cloner (30 day trial), and install on old hard drive
Aattach new hard drive, can be internally or external
OSX will tell you you attached a drive it can’t read and will automatically start Disk Utility for you (this utility is under Applications, then Utilities)
Select the new drive in Left panel, and erase near middle top
Defaults are fine (journaled is the default)
Give it a new name (bottom box) like NewSSD, SSD, or……
Click erase near bottom right
Close Disk Utility when finished (a few seconds)
Run Carbon Copy Cloner (it’s under your applications)
Choose your old hard drive as the SOURCE, top left
Choose your SSD as destination (top right)
On the left middle area, uncheck any large data folders. You can use Finder and Get Info to confirm this. Use a pen and paper to confirm you are leaving off enough data to fit on the new SSD.
Accept the rest of Carbon Copy Cloner defaults (i.e. don’t change the settings)
Click on Clone (bottom right) this may run 45 minutes to several hours depending on whether both drives are internal or one is connected with Thunderbolt, USB or Firewire, and the amount of data you are copying.
Replace your old hard drive with your new SSD or
If you are using LION, you can just go into System Preferences -> System -> Startup Disk and choose the new SSD as the Startup Disk and you don’t have to change any drive positions if both are already setup internally