Things You'll Need
Instructions
Power on the console and allow the XMB bar to load. If your profile has automatically signed in, scroll all the way to the left and select "Sign Out" from the top of the "Users" menu. This will return you to the main sign-in screen. Scroll to the top of the list and select "Create New User." Alternately, you can select this from the "Users" menu at the far left of the XMB while still signed in.
Choose a user name and type it into the box using the on screen keypad. Your PlayStation 3 should connect to the PSN briefly to check that the name is not being used by anyone else. It should not be an issue just yet, as this account only exists on the console itself, and has not been linked to a PSN online account. Press "OK" to create the account and be returned to the sign in screen. Choose the account name you just created and click OK.
Scroll to the far right to the "PlayStation Network" column. Scroll down to "Sign up for PlayStation Network" and select it by pressing "X." Select "Create a New Account," select your country of residence, language, and date of birth. The terms of service agreement will be displayed, scroll to the end and choose "Accept."
Enter a valid email address and select a strong password, using a mixture of upper and lower case letters as well as numbers. Choose a security question and enter your answer. When all of these pieces of information have been confirmed and verified, you will be asked to choose your publicly viewable user name. Enter your desired screen name and press OK. If the name is already in use or contains any flagged words or phrases, the name will be rejected and you will need to choose another.
Enter your full name and address as requested. Then check or uncheck the boxes as appropriate, regarding notifications. Select "Confirm" at the bottom when you are done, and choose an avatar for your account. You are now signed in under the new profile. You and a friend can now sign in under a different profile each and play "Little Big Planet" together, with all the relative saved data kept separate.