Getting Golive 6 to work with MySQL is a bit tricky. You really need to be familiar with MySQL grant tables to get the connection to work properly.
The main thing is to run the Dynamic Content Wizard and enter the ip address of the machine running MySQL FOLLOWED by the MySQL port number (3306) like this: 127.0.0.1:3306
I fyou used this tutorial to get MySQL up and running then use "root" as the username and the password you assigned to the root account in MySQL. Actually, its NEVER a good idea to log into MySQL as root so you really should create a specific user but for local development you should be OK. Search for "GRANT PRIVILEGES" on the mysql documentation website (www.mysql.com) for more on how to set up access permissions in MySQL. if you succeed in getting Golive to connect you'll get a small window showing you a list of the tables installed.
Hope this helps!