The Drupal.org site has a great deal of information on how to theme for Drupal 6. Here is an overview with links to the longer articles.
If you have never themed Drupal before, you are probably wondering about what is involved in the process. Theming for Drupal requires an understanding of:
- Proper front-end web development: (x)HTML + CSS
- The Drupal terminology / theme content tags
- PHP knowledge is a plus, but not necessary
Here is a great screencast video that covers the steps necessary to upgrade a Drupal 5.x installation to Drupal 6.x. Make sure you also read these basic instructions on upgrading from Drupal 5.x, and the video should give you a more comfortable understanding of the steps involved.
Backup a lot and happy upgrading.
This is an extract from the Drupal 6 release announcement. If you are planning to upgrade from Drupal 5.x make sure you read this post carefully:
This is a basic video demonstrating the new Drag And Drop capabilities of the Drupal 6 interface. Its advantage becomes more apparent on the Blocks admin page that can get cluttered with larger sites.
Here is a 9m:24s video covering the installation of Drupal 6 and some of the new modules available with the latest release of Drupal, including OpenId and Actions + Triggers.