Hi,
I have just finished setup with a fresh install of CentOS 5.3 using:

- apache (listening on both port 80 and 1080 for http) 443 for https
- php
- mysql + phpmyadmin
- postfix, dovecot, clamav, spamassassin, amavisd
- iptables + enforcing selinux
- sshd

the question is...
phpmy admin can be accessed simply by digiting
www.mydomain.org/phpmyadmin
when digiting this url phpmyadmin ask me for a user/password and if OK it grant the full access to the database.
do you think that this is a secure way to manage phpmyadmin?
can I do more?

First, what wouldn't hurt, rename "phpmyadmin" on the server to something else, and maybe throw it behind a subdomain.

Second, in your Apache configuration, you can set access privileges on the /phpmyadmin folder by IP. This way, only IPs you allow will have access to the folder. There are a bunch of other things Apache can do for you security-wise in this regard, have a look at Access Control. To accomplish Allow/Deny client filtering, use mod_authz_host.

really kind, thanks!