I would go to mysql.com and download the free mysql administrator gui tool and within that you can set a password.
I installed XAMPP on my Mac, and it was a simple process of downloading a zip file, unzipping it and dragging it into my applications folder. No install procedure, meaning no password set up, so by using MySQL Administrator, I set a password for the root user. At that point, the install of PS3 continued to the next step.
SORRY!! I think this might be redundant now as I didn't see the following pages which I haven't yet read!! I was referring to the struggle to add a password to MySQL root and getting past that step in the installation process of PS3.