I'm working on a script that will (hopefully) make it so that a user's username and password will not need to be entered multiple times while "doing" things on the site...the same way it is with vBulletin basically.

I don't know much about sessions with PHP, but I've heard they're quite useful. Would they be a solid alternative to the use of cookies to accomplish this? Either way, could someone point me to a *VERY* simple tutorial on either feature? I've read the manual areas on PHP.net, but for the most part they're hard to understand...more like reading from a dictionary than a tutorial.