If you want to protect pages from unauthorised access, the simplest way is probably to use .htaccess and .htpasswd (on Apache)
More info here [faq.clever.net]
If it's simply limiting access to a directory on the site, it's fast and easy with .htaccess and .htpasswd files. Some people don't like the generic pop-up windows - (they never bothered me) but they're very simple to create and maintain.
thanks pep's
idiotgirl & sugerkane