Maintaining authentication credentials for session

I've read many docs on how to accept an ID and password throughout a session but it's just over my head I guess!? What I want to do is have someone login, verify that against LDAP directory. If the authentication is accepted, hold the credentials until the user either closes the browser or clicks on a logout link. I'm relatively new to PHP so talk gently! :) I am able to browse and modify user entries using LDAP. That part isn't a problem. Integrating what I have with a session is just hurting my head! Thanks in advance for your help and time. Please advise if I posted to wrong forum! Troy Moreland