Open the config file (eqemu_config.xml) with an editor (notepad works fine) Go down to where you see
Code:
<database>
<host>localhost</host>
<port>3306</port>
<username>eq</username>
<password>eq</password>
<db>eq</db>
</database>
change the eq between <username> and </username> to the user name you used in mysql, change the eq between <password> and </password> to the password you used. If the DB name isn't eq change the eq between <db> and </db> to the db name you used, otherwise leave it alone.
Save the config file and it should work.