Here is a quick tip, to get similar result as php’s array implode function inside of MySQL use GROUP_CONCAT() here is a quick example

SELECT store_orders.*,
(SELECT GROUP_CONCAT(item_name) FROM `store_orderitems` WHERE store_orders.id=store_orderitems.order_id) AS items_purchased
FROM `store_orders`

Here is a good article on mysql_ vs mysqli vs pdo, its cleraly stated that mysql_ should no longer be used.

Which PHP Driver for MySQL should I use

http://www.phparch.com/conferences/webcasts

With recordings of past webcasts.

Thanks PHP Architect

Some slides to think about

PHPAustin Meetup Slides - Software Engineering In PHP

What is Dependency Injection? - Fabien Potencier

http://webcloud.se/article/Building_jQuery_plugins

http://www.phpro.org/examples/PHP-Bullshit-Meter.html

Zend Framework: Surviving The Deep End

The Jobeet Tutorial

Here is a good article from IBM DeveloperWorks on some good object oriented principles to follow
Build seven good object-oriented habits in PHP