Previously, I covered the topic of creating custom regions in Drupal 5 themes. However, Drupal 6 introduced a new process for creating custom regions in themes and it is still one of the topics people ask about most frequently.
So, here's a tutorial on how to create custom regions in your Drupal 6 themes. In this example I will use the Garland theme, and insert a new region called 'Uber content', which I'll position above everything in the main content area.

It's basically a two-step process:
- step 1 - define the custom region in your theme's .info file
- step 2 - insert some PHP in your theme's page.tpl.php file wherever you would like the new region to appear