Further reading

This should grow to a useful list of reading /listening material...

• Drupal.org
• Mustardseed podcast (why did I only find this in March 2010! :-)  )
• Lullabot podcasts, videos, blog
• Drupaleasy podcast
• Drupalmediacamp 2009 in switzerland - proceedings http://drupalmediacamp.ch/presentationen

Books

• The "Using Drupal" book is useful, it can bought as a PDF too. As I was used to Drupal 5, this helped by providing examples that work well on Drupal6 and explains Views and CCK.
• Pro Drupal Development (available as PDF)
• Front End Drupal (available as PDF)
• Drupal 6 - Hagen Graf (introduction in German: not as good as the to above)
  http://drupal.cocoate.com/de/node/1