Gangleri - WordPress does not store the admin password in wp-config.php. It is the database username and password that is being stored there. 99% chance is that your MySQL server would not allow connections from foreign hosts, thus, the person getting the password with Google Code can no nothing with it.
eb001, the password security in WordPress is pretty secure and similar to all the popular applications on the Internet right now, i.e (vBulletin, Joomla).
You can increase security by Admin SSL, as Gangleri suggested. You might also enable .htaccess protection for your wp-admin folder, that way, you have 2 layers of security before anyone can touch your admin panel :)
Good luck.
added: WordPress uses MD5 hash, as does most of the Web Apps out there right now