I am trying to sort out all the stuff myself. I haven't figured out what the best methods of authentication are. I have seen a lot of articles that insist sessions are the answer. From what I know right now I am inclined to favor cookies over sessions (to reduce the load on the server), myself, but that could change in a heartbeat as my knowledge increases. I have not had a chance to dig into .htaccess, ssl, or other types of server security.
Every time I read an article on PHP or MySQL exploits I hafta go through all my code again lol
Here are a couple bookmarks I happen to have handy, but the main reason I am commenting here is to make sure this shows up on my subscribed threads so I am sure not to miss any pertinent comments or links.
http://www.zend.com/zend/tut/authentication.php
http://www.securereality.com.au/archives.html
http://www.phpadvisory.com/articles/view.phtml?ID=5
http://www.devshed.com/Server_Side/PHP/UserAuth/page1.html