I looked for this a few times and didn't find it so I decided to write a quick blog post for future themers to discover. You see Drupal is full of forms and fields. There are any number of reasons that you may want an element on a form to be identified by a unique class or ID. I ran into this today when I wanted to theme a fieldset, provided by a module, that didn't have a class on the fieldset. Now there are many ways to theme a fieldset by using the divs that contain the fieldset.
Cron is one of the most important aspects of having a drupal site. And it can be a pain to figure out, configure, and be sure it's running. I have tried several different processes, and here is the one I like right now...
I have in my theme a directory called plugins.
in there I have layouts and styles
in styles I have a folder called thintop
and... in there I have 2 files (tho I have commented out the template file in favor of this fancy rendering which gives me admin links and extra stuff in my pane...
thintop.inc and THEME-NAME-thintop.tpl.php
(based on http://drupal.org/node/495654)
good info at http://drupal.org/node/427192