How do I edit MySQL settings. When starting SNORT, I get this MYSQL error: access denied for user snort@localhost (using password: YES). I don't recall configuring a password and I can't seem to edit the password.

Most mysql settings are in /etc/mysql/my.cnf

You're supplying a password (or username) that probably doesn't exist; most likely there is no password set for the root mysql user. Why not use that? (Or does snort not let you specify the username/pass?)

Open up a terminal, and try to log into mysql.

mysql -u root (hopefully it won't ask for a password)

If it asks for a password, you can set a new one with:
mysqladmin -u root password new_password

Once you see the mysql prompt (mysql>):
GRANT ALL PRIVILEGES ON * to snort@localhost identified by 'pass-snort-needs';
flush privileges;