Webmin is an excellent program if you need to configure services via web interface. But for standalone system which you will be sitting infront of it, may be not ( unless you insist on using web interface ).Is webmin a useful tool for a standalone p.c. as i have heard it can configure almost everything the O/S needs
When you installed Webmin, it should have asked you who would be the admin person for webmin. If you choose to one of the normal user, then that it's.