The username is shown when you create a database for a website and the password you entered during creation of this database.
i had this question also, this is how i did it: click on the site you want to add the database, then go to the "Options" tab, you will se a button named "New", click on it and it will take you to the "ISP Database" form, type in your password and hit save.. done. make sure you write down the information: Database Name, Database User and Password.
