When Mac OS X is setup on a new Mac, the default computer name is “John’s MacBook” or “Marry Doe’s iMac” depending on the user name you supplied. It is easy to change the computer name with a unique name to allow users on your network to easily find your Mac.
Start up System Preferences from the Apple menu. Click the “Sharing” icon to open the Sharing preference pane.
Click into the “Computer Name” text field and type in the new name you wish to use.
If you wish to further customize the computer name, click the “Edit…” button and fill in the custom info you with others on your network to see.