How do i change my screen name for my PS3 online account?

May be...

I have looked in account settings etc but all you can do is change your name billing details etc. I want to change my screen name. For Example, my name that appears when i am online like Call of Duty4.

You can't change yor PSN ID once you make it. The only way to get a new one is to create a new user and come up with the PSN ID you want. You'll need another email address to register as well.

you cant change it sorry mate. im stuck with a gay name and cant change it