newbie user authentication question

Does anyone have advice for me on user authentication? To gain access to an area of a web site for certain member organizations only, I have created a script that authenticates user names and passwords against a database that using this type of code: if (!isset($PHP_AUTH_USER)) { header('WWW-Authenticate: Basic realm="Private"'); header('HTTP/1.0 401 Unauthorized'); exit; } else if (isset($PHP_AUTH_USER)) { // check the user database for matching name & password....(etc.) The authentication against the database is working fine. My only concern is, how do I make this work on multiple pages? All of the tutorials I've found so far only address a single point of authentication, but I have several pages in the private area of the site that a user could theoretically bookmark and return to without being prompted to log in. Should I copy this code onto each page? Or is there some simple IF ELSE statement I can make on each page to check if they have logged in already? Or do I need to be doing this a different way altogether (such as with sessions)....? If anyone has any advice for me, I'd love to hear it. cheers, Rach ------------------------------------------- Rachel Daniell Media Jumpstart a nonprofit technology resource for NYC nonprofits rachel@mediajumpstart.org 212-894-3386