I installed mySQL and PHP on my computer. When I try to get into the database with PHPmyadmin is asks me for a username and a password for mySQL. Where does this Username and password come from? How do I access them? I am using windows xp home.

Since you installed on your local computer, and if the mySQL install wizard may or may not have asked for a user and password (if it did, use that), its most likely that the userid is set to root and the password is left blank.