Don’t succeeed in publishing my blog

Ok, i’ve installed wordpress 1.2 on my Mac (OSX 10.3) and all work like a charm. I have mysql running and i can edit my blog at http://127.0.0.1/wordpress/wp-admin/post.php and view it at http://127.0.0.1/wordpress/index.php.
Now i want to publish my blog to http://www.mydomain.org. I’ve tried to change wp-config.php, putting http://www.mydomain.org instead “localhost” but it doesn’t work (“Error establishing a database connection! This probably means that the connection information in your wp-config.php file is incorrect.). What do i have to do?
Thank you very much