Your Mac’s computer name is setup automatically by the OS X Lion install program. It uses the name you type in for the registration form during setup, combine with the model of your Mac. For example “Sarah’s MacBook Pro”. This is the name that will appear when you or someone is browsing your computer network.
It is common to name the computers in a network with names from a series, such as Toy Story characters, fruit names or name of constellations. Under Mac OS X, it might not be obvious where are the settings in System Preferences to change the computer name.
The setting to change the computer name is hidden under “Sharing” in System Preferences. Those with MS Windows experience tends to look for it under “Network”. Open System Preferences and click on the Sharing icon.
Click on the box beside “Computer Name” and enter the new name for your computer. That’s it and it is that simple.