Instructions
Power on your PlayStation 3 console, but do not log in to the PSN network. Scroll to the far-left of the cross-media bar (XMB) and highlight the "Users" icon.
Click on the "Create New User" option and enter your new user name. Press the "OK" button to create the account.
Select the current account you are logged into by pressing the "X" button on your PS3 controller. Press the "Yes" button when it asks you if you want to log out.
Select the new user icon that you have just created in Step 2. Scroll to the far right-hand side of the XMB menu and select the "PlayStation Network" icon.
Scroll up to the icon "Sign Up For PlayStation Network" and press the "X" button to select. Complete the PlayStation Network account enrollment process by entering your date of birth, email address, password, full name and home address. You will also be asked to set an online ID for the PS3 Network.
Click the "Create Account" button after you are finished to create the new PSN ID. Once you begin to play online games, you will see your new ID appear when you play.