Is this possible without creating a new user account? I made a bit of a retard move when I got my PS3 and created the account (and just noticed it now - 1.5 years later) by spelling my username wrong! What a noob move....

No it can't.

Your going to need to create a new use account. On the bright side, at least you will be able to transfer all of your saved games over to the new one :) The down side - any ranking you have for your online account (COD4, R:FOM) will be gone :(

Man that really sucks. I have so many games that I play online and i so don't want to loose the rank's that I've built up. Its like starting from scratch all over again.

Why do you want a name change?