Well, I've been battling php and mysql at work, recently - not for creating a shopping cart, but for something simmilar (a request form that holds user information and interacts dynamicly with the user). I'm new to both (mysql and php) but there are cerainly possibilities there - be sure to check out http://www.php.net - their function list is quite extensive, and is has a build in forum kind of thing, where other users make some suggestions - you could start by looking into 'php session variables'... Like I said, I'm no professional, but maybe this gives you a place to start.
