Maintaining sessions across multiple sites

I'm in the process of building an application that has an adminstration back-end shared by multiple sites. I need to maintain a persistent session across these sites to properly identify users. I'm using a db to store the session data but when switching from site to site, a new session_id is started. Does someone know of a good article that explains how to accomplish this effectively? Any help is appreciated. ron ================================== Ron Dyck Webbtech www.webbtech.net ==================================