.htaccess and PHP

Hi I am authenticating users on my website using .htaccess. After they log in, I want to pass the user info (for ex: a unique nr. identifiying the person) thruought all the pages which are affected by the .htaccess file, in order to extract that user's info from the database. I must tell you that authentication has to be done through .htaccess so I can't change that. I have some ideas, but I would really prefer to hear some of your thoughts on this one. Hope you understood what I want. :):) Smad