We have a new joomla 1.5 template quick reference guide, which contains most of the joomla 1.5 CSS ids and classes, some info about the index.php and module chrome. You can identify which HTML tags are affected by the joomla CSS classes and ids, and we also give some explanation when needed. It is classified in a way that makes it easier to overview the topic. This joomla template quick reference guide is freely available, but you have to sign up here.