Using Drupal A great Drupal cook book – not only a fun way to start but gives you a high level view of what Drupal can be used for
Pro Drupal Development Dives into the deep end and come out on the other side with all you need to know
Flash with Drupal This book will not only teach you on using Drupal with flash but also teach you how flash really should be used. Also really useful for learning about the Drupal API